IMPCO LPG RETURN TO: MAIN INDEX RETURN TO: SERVICE MANUAL INDEX

IMPCO LPG RETURN TO: MAIN INDEX RETURN TO: SERVICE MANUAL INDEX GENERAL COMPONENTS IN BRIEF (LPG SYSTEM EXCLUSIVE TYPE) ENGINE REGULATOR SHUTOFF VALVE CARBURETOR LPG SYSTEM PIPING (PROTECTION FROM GAS LEAKAGE) TROUBLESHOOTING

FOREWORD This repair manual describes the construction, operation and repair method of LPG system devices (LPG exclusive type) mounted on the Toyota forklift trucks. Specifically they are as follows: Pneumatic model Cushion model Model Engine Model Engine 42-6FGU15, 42-6FGF15 4Y 42-6FGCU15 4Y 42-6FGU18, 42-6FGF18 4Y 42-6FGCU18 4Y 42-6FGU20, 42-6FGF20 4Y 42-6FGCU20 4Y 52-6FGU20 GM 52-6FGCU20 GM 42-6FGU25, 42-6FGF25 4Y 42-6FGCU25 4Y 52-6FGU25 GM 52-6FGCU25 GM 02-6FGU30, 02-6FGF30 4Y 42-6FGCU30 4Y 52-6FGU30 GM 52-6FGCU30 GM This Manual has been compiled to provide you with useful information on the proper maintenance of Toyota s forklift to maintain its high performance and excellent durability sufficiently for a long time. This manual has been edited on the basis of the data available as of June 1995. Kindly consult the Parts & Service News for any subsequent changes or modifications. TOYOTA MOTOR CORPORATION

0-2 LPG SYSTEM PRINCIPLE LPG SYSTEM EXCLUSIVE TYPE The LPG in the liquid state taken out from the cylinder passes the filter and shutoff valve in the engine room for filtration of foreign matters, and enters the regulator. The LPG subject to pressure reduction by the regulator changes to the gaseous state and is taken into the engine via the carburetor. As the heat source for gasification of LPG, the warm water after cooling the engine is led to the regulator. The fuel system comprises liquid withdrawal type fuel container, hydrostatic pressure relief valve, fuel filter, mechanically operated valve, vaporizer-regulator, carburetor, and interconnecting LP-Gas fuel hose. The fuel line is routed through manual shut-off-valve on the fuel container, through quick-connect coupling on flexible fuel line, and through fuel filter to mechanically operated shut-off-valve. The mechanically operated shutoff valve is connected in series with the engine vacuum system. The shut-off-valve is energized only when the engine develops vacuum pressure by cranking. When energized, the mechanically operated shutoff valve permits the fuel to flow through the vaporizer regulator to the carburetor. The vaporizer-regulator is connected to the engine coolant system so that the coolant is circulated around the assembly to assist in fuel vaporization. Tank bracket which horizontally mounts 33-1/2 LB capacity Listed LP-Gas container (STD) for industrial truck is mounted on the pillars above counterweight. The tank is secured by bracket with a clamping strap. Pin secured to the container bracket to assure positive location of the fuel container.

0-3 ABBREVIATIONS GENERAL RULES FOR SERVICING WORK PREPARATION BEFORE DISASSEMBLY 1 2 Prepare mechanic tools, necessary measuring instruments and SST before starting operation. When disassembling a complicated assembly, put punch or matching marks at places not affecting the function to facilitate reassembly operation. When repairing an electrical system, start operation after disconnecting the cable from the battery negative terminal. INSPECTION DURING DISASSEMBLY 1 Each time parts is removed, check the parts installed state, deformation, damage, roughening state and scratching. ORDERLY ARRANGEMENT OF DISASSEMBLED PARTS 1 Disassembled parts shall be arranged orderly. Distinguish the parts to be replaced from the parts to be reused. CLEANING OF DISASSEMBLED PARTS 1 Parts to be reused shall be cleaned and washed thoroughly. INSPECTION AND MEASUREMENT 1 Detailed inspection and measurement shall be carried out as required for parts to be reused. INSTALLATION 1 2 3 4 Install good parts according to the correct procedure and observing the determined standards (tightening torques, adjustment values, etc.) Always use genuine parts for replacement of existing parts. Always use new packings, gaskets and cotter pins because they are not meant for reuse. Coat sealant on gaskets depending on the places, coat oil on the sliding contact places, coat oil or grease at specified places, and coat MP grease on oil seal lips before reassembly. ADJUSTMENT AND OPERATION CHECK 1 Adjust to the service standard values by using gages, a multimeter, etc.

0-4 GENERAL RULES FOR LPG SYSTEM REPAIR Due to its high pressure, it can be said that LPG has a tendency to be more leaky. Should LPG once leak however, it turns into gaseous state, and expanding 250 times greater, settling in low spot as 1.5 heavier than air (100% LPG). Any flame or spark could cause a fire or explosion that could cause serious injury. (Ignition temperature 481 (897 F) for 100% LPG.) Utmost care therefore should be exercised for ventilation whenever the repair work is processed. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Before disconnecting any part of the engine fuel system of LP gas-powered trucks, close LP tank valve and run engine until fuel in system is depleted and engine stops. If the engine will not run, close LP tank valve and vent fuel slowly in a nonhazardous area. Handle LP gas cylinder with care. Physical damage such as dents, scrapes, or gouges may dangerously weaken the tank and make it unsafe for use. Whenever the LPG truck is unused, LPG tank valve should be closed. The same is true when transporting the trucks by ship or container. Do not stop or park LPG truck in a place with such a fire source as lit cigarette, match flame, lighter flame, stove, gas burner, electric heater, electric equipment (motor, etc.), or bonfire. Avoid a place exposed to direct sunlight as much as possible since LPG temperature rises accompanied by gas pressure rise. Do not operate an LPG truck in places involving any fire source. Anything ignitable must put away. When operating, inspecting or repairing an LPG truck, put a NO Fire notice board to prevent anybody from approaching with a fire source. When repairing an LPG truck, pull the ignition key off to prevent anybody from operating the faulty truck without knowing it. For gas leakage check, always use a gas leak measuring device (if available), soap water and pressure meter for the regulator. When performing gas leakage check at night, turn on a work light outdoors before approaching the truck for inspection (because a spark by switching is apprehended). If gas is leaking, check no fire source and provide good ventilation. LPG cylinders shall be stored especially carefully in a place without a fire source and installed with a gas leak detector and alarm. Impurities in the fuel and tank rust will be accumulated in the LPG device through long period of operation. Device disorder may result from various reasons. In such a case, the LPG device requires inspection, repair and cleaning. The regulator, especially, shall disassembled and reassembled with sufficient attention paid to the adjustment and airtightness. Always use sealant LOCK TITE 567 on the taper threaded portion of each fitting (union, valve, etc.). Do not smear the leading two threads at the tip end with sealant. Battery, wiring or any electric equipment should not be shorted. It should be confirmed that there is no leak gas staying in atmosphere when the engine is to start.

0-5 PERIODIC MAINTENANCE INSPECTION METHOD I : Inspection. Repair or replacement if required. C: Cleaning *1: Soap water *2: Detector PERIODIC REPLACEMENT PARTS STD conditions are the same as those of the STD and high performance filters.

1-2 COMPONENTS IN BRIEF (LPG SYSTEM EXCLUSIVE TYPE) COMPONENT PARTS 2316 2316-052 2311 2311-121

AIR VALVE FUNCTION The advantages offered by the air valve system include the fact that it operates on the most reliable signal available for detecting engine operation - pressure. Operation pressure is determined by the main link spring (A) that closes the air valve (B). When air valve downflow vacuum pressure (C) is about 6 inch water column (11.2 mmhg)* or greater, the air valve opens. The vacuum pressure from the air valve downflow draws fuel through the regulator fuel passage (D), and causes the shut off valve to activate via hose (a). *1.37 kpa (0.014) kg/cm 2 ) [0.2 psi] When the engine is off, the tip of the air valve and the rubber sheet in the carburetor act to shut off the LP gas flow. Thus, the flow of gas is cut in three places, including the regulator and shut off valve. In other words, each component like the shut-off valve, the carburetor and the regulator has the safety function so as not to let out the gas in case of other parts failure in the system such as hose disconnection, engine stop, having self sealing function. 1-3 LPG System on GM engine (LPG) Exclusive)

1-4 LPG CONTAINER BRACKET AND CONTAINER 1. LPG Container Bracket. Two years are welded on plates of the steel pipe ends. One for rotating, the bracket is fixed to the overhead guard with hinge and the other for locking the bracket to the frame, is fixed to the stay, welded to the overhead guard. Remarks: The tank and hose shown in the illustrations on this page are none-standard parts. Steel semicircular strap with toggle latch strap is jointed to hinge that is welded by the lower steel band. The steel band is welded on the steel pipes. Elastic rubber bands are used to provide the tank with secure grip. The engine hood cannot be opened without swinging out the bracket of LP-gas container bracket. The tank bracket is provided with a stud that determine the tank position in circumferential direction. The tank is provided with a match hole for position setting on the bracket. Caution: Take care for any improper joint, such as for a latch, hinge, and band that causes instability of the tank.

2. LPG Container. The LPG Container is fixed on the LPG bracket tightly with the rubber bands and the metal strap provided with latches on the ends. And UL approved containers are adopted. Since the explosive gas is used, care must be used before starting inspection and the repair, such as good ventilation, and separation from ignitable source. Caution: (1) Before disconnecting any part of the engine fuel system of LP gas-powered trucks, close LP tank valve and run engine until fuel in system is depleted* and engine stops. If the engine will not run, close LP tank valve and vent fuel slowly in a nonhazardous area. * Even the empty tank, it is still inflamable and explosive. (2) Handle LP gas cylinders with care. Physical damage such as dents, scrapes, or gouges may dangerously weaken the tank and make it unsafe for use. * LPG tank is also called LPG container or LPG cylinder. 1-5

1-6 SPECIFICATION *1 Tank inside pressure when filled full with liquid LP gas. *2 Test pressure on Manufacturing. *3 When filled with liquid LP gas up to the Max. gauge (up to 80% Limiter tube), LP gas weight will be approx. 15.2 kg (33.5 lbs) (STD model) and 9.1 kg (20 lbs) (Option). EQUIPMENTS 1 Service valve 2 Manual coupling 3 High pressure hose 4 Tank relief valve 5 Sight gauge 6 Fill valve 7 Relief valve (See Page 1-8)

1-7 1 2 Service valve The service valve is the outlet for fuel. When use, fully open the valve. When unuse, close tight with a hand. Quick coupling To ease the tank removal for charge, the quick coupling (manually operable thread secured coupling) is used on the end of the high pressure hose at the tank side. When the coupling is disconnected, LP gas releasing from the tank is stopped by the valve in the quick coupling. On every occasion however, care should be exercised to fasten the tank service valve. Caution: l Close the tank service valve tight when unused. l The manual coupling must be tightened fully till reaching to the end, otherwise gas leaks. l Wear glove when handling the LPG tank to protect skin from freezing. l The tank is too heavy to mount or dismount by one person, i.e. Tare weight 16.3 kg (36 lb) plus Gas weight Max. 15.2 kg (33.5 lb), makes 31.5 kg (69.5 lb) for the STD tank. Ask assistance, or use proper lifting means. 3 High pressure hose Caution: Since the hose is moved about every time the engine hood is opened, care should be used for sustaining damage. 4 5 6 Tank relief valve This is the pressure relief valve when the gas is filled full. The gas should be filled until the liquid gas leaks out there. Leaked gas should be wiped off, and the vinyl cap should be put on. Sight gauge Remaining gas volume in the tank can be checked by the gauge. The volume is distinguished by color zone, and pressure figures. When the needle enters in the empty zone on the gauge, the tank should be refilled. Fill valve The valve for filling the gas. Do not tamper with it.

1-8 Relief valve The relief valve is installed between the tank and the filter w/ shut-off-valve. It has only an emergency function to protect the LPG tank from explosion. If the tank should undergo extreme high heat and inner pressure would rise to hazardous extent, it relieve excess pressures. The relief valve was preset safety device, don t disassemble. FILTER AND SHUT OFF VALVE IMPCO VFF 30 filter and shut-off-valve (UL approved) is adopted. The shut-off-valve is operated by negative pressure gener-

1-9 WORKING PRINCIPLE The leaf spring presses the valve to the seas. When negative pressure arises by engine running, a slight negative pressure at 493 Pa (3.7 mmhg) [2 inaq] starts to open the diaphragm and the fuel comes through the filter. (The leaf spring presses the valve to the seat.) When negative pressure arises, the diaphragm presses the valve to open as overcoming the leaf spring force. REGULATOR The regulator is an IMPCO model K (UL-approved). The liquid fuel passing from the tank through the filter and shut off valve are depressurized in two stages to a point slightly lower than atmospheric pressure. When the engine is cranking to start or in operation, the vacuum generated in the fuel passage activates the regulator. Liquid propane is gasified by depressurizing it from its approximately 1.65 MPa (16.88 kg/cm 2 ) [240 psi] pressure in the tank to atmospheric pressure. Engine coolant is circulated through a warm water circuit in the regulator to assist in gasification. When the engine is stopped, fuel circulation is stopped by the secondary

1-10 CARBURETOR FUNCTIONAL PRINCIPLE (GM) All but one model of the IMPCO air valve carburetors use diaphragms of fiberglass and synthetic rubber or silicone material. Model 50 uses a metal piston with a sealing ring in place of a diaphragm for the purpose of reducing the carburetor size for small engines. The principle applied is the same for both. Cranking the engine lowers pressure in shaded area as piston descends. Through passages (P) in the air valve, lowered pressure is communicated to upper side of diaphragm (D). As a result, atmospheric pressure pushing upward on the diaphragm lifts it against the downward pressure of the metering spring (S). Approximately 1.37 kpa (0.014 kg/cm 2 ) [0.2 psi] 1495 Pa W.C. (152.4 mm W.C.) [6 in W.C.] of pressure is required to lift the air valve off its seat. Approximately 3.45 kpa (0.035 kg/cm 2 ) [0.5 psi]; 350.5 mm W.C. (13.8 in W.C.) lifts the valve to the top of its travel in full open position. Lowered pressure communicated to the top of the diaphragm varies with engine speed and position of throttle valve opening (T). The air valve assembly measures the air flow into the engine by moving precisely in response to the demands of the engine and throttle valve position. The controlled pressure drop of 1.37 ~ 3.45 kpa (0.014 ~ 0.035 kg/cm 2 ) [0.2 to 0.5 psi] (6" ~ 13.8" W.C.) set up by the metering spring provides the signal or force necessary to draw fuel into the air stream within the carburetor. The gas metering valve (V) is attached to the air valve assembly and is shaped to admit the correct amount of fuel from the gas jet to mix with incoming air at any opening of the air valve. 1. Idle Air Bypass Adjustment (I) The total volume of air and fuel passing the closed throttle at idle is constant. The idle adjustment bypasses a portion of incoming air around the air valve opening. As the idle adjustment is opened, the air valve partially closes, thereby closing the gas metering valve and leaning the idle air-fuel mixture. 2. Power Mixture Adjustment (A) Controls mixtures when gas metering valve is withdrawn from the jet. This adjustment is effective only when the engine approaches full-load condition and can be set only with the engine loaded, at or close to its rated RPM limit. Mixtures between idle and full-load conditions are controlled by the gas metering valve shape. The gas metering valve is shaped to produce lean mixtures at light loads and increasingly rich mixtures at heavier loads and higher engine speeds. The shape of the gas valve is designed for optimum mixtures for the mid-size engine between the largest and smallest cubic inch displacement upon which the carburetor will be installed.

As compared with the carburetor for gasoline trucks, the structure is simple and almost no trouble occurs. As the tar type substance or dust in the fuel may adhere in the carburetor to cause engine performance degradation, periodic overhaul is recommended. 1-11 4Y GM RELATION BETWEEN EACH DEVICE AND PIPING

2-2 ENGINE SPECIFICATION 1) 4Y ENGINE

2) GM ENGINE 2-3

2-4 ENGINE PERFORMANCE CURVES (LPG EXCLUSIVE TYPE) 4Y Engine on Pneumatic Model: 1 2 ton Series

4Y Engine on Pneumatic Model: 3 ton Series 2-5

2-6 4Y Engine on Cushion Model: 1 ton Series

4Y Engine on Cushion Model: 2 3 ton Series 2-7

2-8 GM Engine on Cushion Model & Pneumatic Model: 2 3 ton Series

2-9 ENGINE ADJUSTMENT IGNITION TIMING INSPECTION AND ADJUSTMENT (1) Engine warning up Standards Coolant temperature : 80 C (176 F) or above Engine oil temperature : 70 C (138 F) or above Hydraulic oil temperature : 50 C ( 122 F) or above (2) Tachometer and timing light installation <4Y Engine Truck> Disconnect the test connector of the IIA (distributor) and connect the tachometer measuring cord black wire. <GM Engine Truck> Set the tachometer and the timing light. Disconnect the inspection connector, and connect the tachometer to the male side of the connector. (3) Idling speed <4Y Engine Truck and GM Engine Truck> 750± 50rpm 0 (4) Ignition timing inspection and adjustment <4Y Engine Truck> 1 Disconnect the vacuum hose from the IIA (distributor). 2 Check the ignition timing with the timing light. 7 BTDC/750 rpm 3 If the standard value is not satisfied, loosen the distributor set bolt and rotate the distributor for adjustment to the standard value. 4 Tighten the set bolt and inspect the ignition timing again. T = 18.14 N m (185 kgf-cm) [13.38 ft-lb] 5 After the ignition timing adjustment, seal the distributor set bolt with sealing tape. <GM Engine Truck> 1 Check the ignition timing with the timing light. 12 ± 2 BTDC/750 rpm 2 If the standard value is not satisfied, loosen the distributor set bolt and rotate the distributor for adjustment to the standard value. 3 Tighten the set bolt and inspect the ignition timing again. T = 25.9-48.1 N m (264-491 kgf-cm) [19-36 ft-lb]

2-10 AIR GOVERNOR ADJUSTMENT (w/gm ENGINE-LPG ONLY TYPE) Note: In prior to the air governor adjustment, the carburetor adjustment should be done properly. 1. Function of Each Adjusting Part: 1 Set screw To lock the Bush. 2 Bush To raise or lower the no load max. rpm. To raise, turn clockwise, and to lower turn it counter clockwise. Note: When turning the bush, hold the 3 screw with a screw driver so as not to allow the screw to be turned together. 3 Screw To turn counter clockwise, the tilt relief down is made smaller. When the tilt relief down rpm is adjusted within the specified range, turn back the screw by 1/10 turn to eliminate the leaf spring twist. Turn the 3 screw clockwise. Then turn back 1/4 turn counter clockwise, and again turn clockwise by 1/10 turn to prevent the spring from twisting, and to avoid hunting.

2-11 2. Sequence of Air Governor Adjustment (1) Warm up the engine Engine oil temperature: More than 60 C (140 F) (2) Adjust the no load maximum rpm to the specified 2600± 50 rpm with the 2 bushing. (3) Adjust the tilt relief down rpm with the 3 screw within 250 rpm. (4) Minimize hunting* with the 3 screw. (5) Lock the bushing and screws with a wire and sealing lead as shown: Adjust value: 6FGU20-30 6FGCU20-30 W/GM engine No load Max. rpm: 2600 ± 50 rpm down at tilt relief: Less than 250 rpm *Hunting: Deviation of the rotational speed with hunting width of ±20 rpm for more than 5 seconds.

3-2 REGULATOR COMPONENT PARTS 1 Screen Vent, Atmospheric 2 Screw, 8-32x5/8" (6) 3 Cover Assy., Secondary, Hydrin 4 Diaphragm Assy., Secondary 5 Screw, 8-32x3/8" SEMS 6 Lever, Secondary Regulator 7 Pin, Secondary Fulcrum 8 Seat, Secondary Regulator 9 Spring, Secondary 10 Body Assy., w/jet 11 Plug 12 Screw, 1/4-20x5/8" SEMS (2) 13 Gasket, Body to Plate 14 Plate, Converter Body Cover 15 Plug, 1/8" Pipe, Hex Head 16 Spring, Primary Regulator 17 Primary Valve Pin, w/o-ring 18 Diaphragm, Primary Regulator 19 Cover, Primary Regulator 20 Screw, 8-32x1" SEMS (7)

3-3 REGULATOR REPAIR METHOD Note: 1. Numbers in Parenthesis, as (3), refer to Index No. in exploded view on Page 3-2. 2. Do NOT use Teflon thread tape on any of the NPT pipe-thread fittings where fuel travels. Use a suitable fuel-resistant joint compound. 3. Be sure to leak-check all fittings and covers for fuel leaks, using a soapy solution. 4. Be sure to use proper mounting bolts to secure the converter. Bolts which are too long may cause severe damage to the converter. 1. Begin disassembly of regulator by removing secondary cover (3) assembly. Take out six screws (2) to loosen cover. 2. Break cover loose by tapping around circumference with plastic screwdriver handle. 3. Remove secondary cover (3) and secondary diaphragm (4) as a unit. Note tab of secondary regulator lever protruding through slot in metal tab on secondary diaphragm. Slide cover and diaphragm forward to free lever from slotted hole. Be careful not to bend the secondary lever.

3-4 5. Remove regulator lever retaining screw (5). 6. Lift secondary regulator lever 16), exposing secondary spring (9). Be careful not to lose fulcrum pin (7), located in regulator lever. Set assembly aside and remove spring. 7. Turn converter over. Remove seven screws (20) and lift off primary regulator cover (19). 8. Primary cover (19) and primary diaphragm (18) are shown removed. Note triangular lever riveted to diaphragm. This lever is supported by a fulcrum cast in the cover and depresses the primary valve pin (17) and primary spring (16). Pen points to pressure regulator sensing port. 9. Remove primary valve pin (17) as shown, then lift spring (16) from body. Discard pin; retain spring.

3-5 10. Remove cover plate (14) and gasket (13) exposing vaporizing chamber in body and heat exchange labyrinth used to heat vaporized fuel. 11. Remove gasket (13) from cover plate (14). Clean cover as required for good seal with new gasket. Reverse process to install new gasket and existing cover plate on body. Be careful to align hole in gasket (white arrow) with small hole in cover plate (black arrow). 12. Insert new primary valve pin (17) from kit and existing primary spring (16). Note raised platform which forms spring seat. Do NOT install pin and spring in pressure regulator sensing port, shown in step 8. 13. Set new primary diaphragm (18) from kit on converter body. Screw-hole spacing prevents improper orientation of diaphragm. 14. Carefully place primary cover plate (19) over diaphragm and hand-thread screws (20) through cover and into body.

3-6 15. Torque screws (20) to secure primary cover plate. Tightening torque: T = 2.37 N m (24.19 kgf-cm) [1.75 ft-lb or 21 in-lb] 16. Use side-cutters to remove nose of soft secondary regulator seat (8) from secondary regulator lever (6). Discard seat. 17. Push nose of new regulator seat (8) from kit through hole in end of regulator lever (6). 18. Note relationship of three components of secondary regulator assembly: secondary spring (9), secondary regulator lever (6) and fulcrum pin (7) prior to assembly. 19. Set spring (9) on its seat on converter body, then position lever and pin assembly (6, 7) on top of spring. Push down until pin seats and hold in place...

3-7 20. then position screw (5)... 21. and secure assembly with screwdriver. 22. Illustration shows relationship of secondary diaphragm slot (4) and end of secondary regulator lever (6), which must protrude through slot when installing new diaphragm. Hold edges of diaphragm while pressing central metal diaphragm plate down, forming a cone. Watch to be certain lever engages slot. Diaphragm may be installed in either of two positions which engage slot and lever. 23. Add secondary cover (3) and install screws (2). 24. Torque screws to complete repair kit installation. Tightening torque: T = 2.37 N m (24.19 kgf-cm) [1.75 ft-lb or 21 in-lb]

4-2 SHUTOFF VALVE COMPONENT PARTS 02. Valve W/ filter assy 11. Filter body assy 12. Filter assy 44. Diaphragm cover 45. Diaphragm assy AM. Retainer AN. Valve lever AO. Seal washer AP. Valve seat AQ. Pin AJ. O ring AR. Valve spring AT. Filter screen AW. Filter cover 01K. O/H Kit Vacuum Fuellock-Filter Components

4-3 SHUTOFF VALVE REPAIR METHOD 1. Remove 10 screws from Fuel In cover. 2. Remove cover and gasket. 3. Remove filter and screen. 4. Remove screw holding valve spring. 5. Remove valve spring.

4-4 6. Remove valve seat. 7. Remove valve operating pin. 8. With paper clip or wire, fashion a hook as shown. 9. Insert hook in hole in seal retaining washer and remove. 10. Washer removed.

4-5 11. Same hook tool ready to remove O ring seal through valve jet. 12. Insert tool through jet. 13. Pick out O ring. Wash body, cover and jet area clean as needed. (Use kerosene or equivalent petroleum solvent. Do not use carburetor cleaner as it will attack synthetic rubber seals.) 14. Kit includes: Gasket Filter Screen Diaphragm Assy Screws, 8-32 x 5/8" Screws, 12-24 x 5/8" Seat (Viton Bonded to Aluminum) Seal, O ring Pin, Valve Operating 15. Coat silicone grease on a new O-ring.

4-6 16. Insert the O-ring carefully without dislocation sideways. 17. Reverse the valve operating pin and sufficiently push in the O-ring. 18. With O ring in place in its recess, use needle nose pliers to hold seal retainer washer. 19. Insert seal retainer washer in slot to hold O ring in place. 20. Insertion of valve operating pin will retain washer and O ring in place.

4-7 21. Valve seat shown with aluminum side up ready to be placed on jet. 22. Seat, viton (rubber) side down, in position on jet. 23. Valve spring ready to be fastened in place. 24. Spring fastened in place by screw (8-32 x 5/16"). In lightening screw, hold tip of spring (over valve) centered between the 3 guide fins as shown here to avoid friction. 25. With spring in place, lift it slightly to assure freedom of travel.

4-8 26. Insert screen in recess as shown. 27. Insert filter in recess over screen. 28. Place gasket in place. Align with screw holes. 29. With 2 opposite screws in Fuel In cover, lower cover on to gasket and start two screws in their threads. 30. After examining position of gasket through remaining open holes to insure correct alignment, insert remaining 8 screws in their openings.

4-9 31. Tighten screws, alternating from side to side on opposite sides of the cover until all screws are solidly set. 32. Fully loosen 6 screws on diaphragm cover side as shown. 33. Remove cover and diaphragm assy. 34. Clean parts as necessary. (See instructions in step 14 for cleaning.) Check lever for free travel and check lever control pin to see that it follows lever travel. Prepare to install new diaphragm assembly with gasket side toward body as indicated in photo. 35. Turn diaphragm to position where its screw hole pattern matches holes in body. There is only one position in which the holes will line up.

4-10 36. Place cover in correct position. 37. Tighten screws alternately from side to side across cover until all are solidly fastened. Pressurize the Fuel In opening with air or fuel. Check fuel outlet and fuel inlet cover gasket for leaks with soap suds or testing solution.

5-2 COMPONENT PARTS CARBURETOR ON 4Y ENGINE LPG EXCLUSIVE TYPE 2312 2312-017

5-3 CARBURETOR ON GM ENGINE LPG EXCLUSIVE TYPE 2312 2312-018

5-4 CARBURETOR REPAIR METHOD (4Y) 1. Remove the carburetor from the engine, and remove two nuts mounting the flange adapter. 2. With carburetor removed from engine, remove 4 screws holding throttle body to mixer bowl. 3. With throttle body removed, note that gasket retains idle cutoff piston in place (under finger tip). 4. Remove gasket. Idle cutoff piston and spring are released. Do not lose either one. 5. Remove check valve plate and air valve spring. Lift air/gas valve from mixer bowl.

5-5 6. Clean mixer bowl assembly in kerosene or equivalent petroleum solvent. Do not use carburetor cleaner as it will attack synthetic rubber seals. 7. Kit includes: Air-Gas Valve Assy Ring, Sealing Plate, Check Valve Gasket, TB to Mixer Screw, 10-24 x 5/8" Piston, Idle cutoff Spring, Idle cutoff Instruction 8. Install sealing ring in piston groove. Install one end in groove and coax the ring in spirally to avoid breaking or creasing the ring. 9. Replace air/gas valve assembly in mixer bowl. Tilt valve slightly to insert one end of the split sealing ring into the cylinder of the bowl. Then, using pencil lead or similar point, slide around circumference of sealing ring pressing it in until ring and assembly drop into the bowl. 10. Note: When installing the air/gas valve assembly it is recommended that a lubricant such as WD-40 be sprayed onto the mixer body well. This eliminates the possibility of the air/gas valve assembly sticking to the body. Replace air/valve spring and check valve plate in the mixer bowl.

5-6 11. Shows mixer bowl assembled with check valve assembly centered towards air horn. The idle cutoff piston and spring are shown in place ready for assembly to the mixer bowl. 12. Gasket in place retaining idle cutoff piston in its recess (under thumb). 13. Invert throttle body, holding gasket and idle cutoff piston in place. Note cutout of gasket to clear check valve assembly on plate. 14. Lower throttle body gently onto mixer bowl making sure idle cutoff piston does not escape from its recess. With throttle body flush on the mixer bowl, align the holes and start the 4 screws. Note: When installing the air/gas valve assembly it is recommended that a lubricant such WD-40 be sprayed onto the mixer body well. This eliminates the possibility of the air/gas valve assembly sticking to the body. 15. Tighten 4 screws. T = 3.43 ~ 4.51 N m (35 ~ 45 kgf-cm) [2.53 ~ 3.33 ft-lb]

16. 17. With assembly completed, reach a forefinger into the carburetor air horn and lift air valve several times to check free movement. Air valve should lift easily and return slowly due to action of check valve. Install the gasket and flange adapter, and tighten two nuts. T = 6.47 ~ 8.43 N m (65 ~ 85 kgf-cm) [4.70 ~ 6.15 ft-lb] 5-7

5-8 CARBURETOR REPAIR METHOD (GM) T = N m (kg-cm) [ft-lb] Disassembly Procedure 1 Remove the spring. [Point 1] 2 Remove the bushing. 3 Remove the split lock washer. 4 Remove the throttle stop lever. 5 Remove the idle stop spring. [Point 2] 6 Remove the throttle valve body Assy. 7 Remove the spacer. 8 Remove the hose fitting (to the air governer). 9 Remove the pan head screw. 10 Remove the idle adjustment spring. 11 Remove the air valve cover. 12 Remove the air valve spring. 13 Remove the air-gas valve assembly. [Point 3] 14 Remove the mixer body. Assembly Follow the reverse order of Disassembly.

5-9 Point Operations [Point 1] Reassembly: When hook the spring to the roller, install it in correct orientation, as shown. [Point 2] Reassembly: When the throttle valve is closed the orientation of each parts, such as the idle stop crew the split lock washer, are as shown, i.e. (1) The split washer cable guide is outside, and the angle of installation is as shown. (2) Tip of the idle speed adjust screw end touches to the throttle stop lever.

5-10 [Point 3] Inspection: (1) Check the diaphragm for damage by disassembling. Even a slight fissure may affect the pressure balance function. (2) Check the negative pressure orifice for clogging. If clogged, clean. Assembly: When installing the air-gas valve assembly, the ridge portion should be directed to the fuel inlet side.

5-11 CARBURETOR ADJUSTMENT The power adjuster (C) of the carburetor shown below is for adjustment of the fuel concentration at full throttle. Since it has been adjusted for 100% propane used in the United States, do not tamper with the power adjuster. Make idling adjustment as required by means of (A) and (B) shown in the figure below. Idling Adjustment As the idling speed and CO concentration at idle in the LPG vehicle greatly influence the idling stability, engine tenacity and startability, they shall be set to the standard levels. Standards Idling speed (rpm): 750 CO (%): 2 ~ 3 +50-0 Adjustment Procedure Adjusting Parts Part Name Purpose Increase/decrease by counterclockwise rotation (A) Idle adjusting Fuel flow Decrease screw rate adjustment (B) Throttle Air fuel mixture Decrease adjusting screw flow rate adjustment (1) (2) (3) (4) (5) (6) Warm up the engine. Adjust to the standard idling speed by turning (B). (If the standard speed is not attained, make adjustment after turning (A).) Slowly turn (A) clockwise or counterclockwise to find the area where the speed is maximized. Adjust to the standard idling speed by turning (B). Repeat steps (3) and (4) to turn (A) and determine the opening of (B) where the highest speed equals the standard speed. Slowly turn (A) counterclockwise to find the opening where the speed starts to drop, and turn it clockwise by 45 from the opening. The standard idling speed and CO concentration 2 ~ 3% are obtained in this state.

6-2 LPG SYSTEM PIPING (PROTECTION FROM GAS LEAKAGE) GENERAL When conducting proper LP-gas leakage test on the high pressure LP-gas fuel system employing soap and water solution or equivalent as a detective means, it is required that there shall be no leakage while the system is under gas pressures of not less than 620 kpa (6.4 kg/cm 2 ) [90 psi]. Test equipments and facility should be used for the gas leakage test. If you are obliged to make the test where no such provisions are available, the test can be performed by opening the LPG tank outlet valve and running the engine. In this method however, it is difficult to ascertain whether gas will leak later, especially when ambient temperature is low, since gas (vapour) pressures required for the test can not be obtained. It is also difficult when the engine fails to start even several repair attempts have been done. Good quality LPG is essential, too. If propane percentage is lower, vapour pressure becomes lower. Relation between temperature, propane percentage and vapour pressures is as shown: If 100% propane is used, vapour pressure exceeds 620 kpa (6.4 kg/cm 2 ) [90 psi] when temperature reaches over 15 C (59 F).

6-3 COMPONENT PARTS 2311 2311-121

6-4 GAS LEAKAGE TEST Essential points will be explained in accordance with the number shown in the illustration. POINTS IN COMMON 1. Inspect all the connection between the quick coupling 1 and the regulator 5 with soap and water solution under gas pressures of not less than 0.62 MPa (6.4 kg/cm 2 ) [90 psi]. 2. Installation Procedure for LPG fitting at Tapered Port. Where tapered thread fittings are used for the elbow, straight fittings as the union, follow the next steps: (1) Inspect to ensure that both mating parts are free of burrs, nicks or scratches, and remove all dirt and debris such as old sealant, grease, oil and metallic particles from the thread portion.

(2) Apply Loctite PST pipe sealant 567 around male thread so that applying width is more than 1/3 of thread length. Applying range starts from 3rd thread of tapered screw end. (3) Tighten external thread by 29.4 N m ± 4.9 N m (300 ± 50 kgf-cm) [21.71 ± 3.62 ft-lb]. However, tightening torque of the elbows whose installing directions are specified should be 24.5 kpa (250 kg-cm) [18.09 ft-lb] or more. (4) After assembly, leave it for 3 hours or more to dry sealant. Caution: This procedure must be strictly followed whenever an LPG fitting is found to be leaking or requires loosening or disassembly and assembly for any reason. Failure to follow this procedure may result in gas leakage which could create the potential for serious injury from fire or explosion. 6-5 ESSENTIAL POINTS ON ROUTE (Number in circle corresponds to a drawing on page 6-4.) LPG container. High pressure hose. Tighten the quick coupling by a hand to the end of the screw, and check it for leakage, including the fitting and the high pressure hose. For the high pressure hose, check not only the joint portion, but also the rim portion of the crimped metal. The connection between the coupling and the elbow is taper threads. (See point in former paragraph.) ƒ Junction All the connections to the junction block use taper thread, such as the elbow, the relief valve and the fitting. (See point in former paragraph.)

6-6 Note: Don t disassemble the relief valve, except for the removal as a unit from the taper threads, since it was preset for the safety precaution. Where the gas pressures of 620 kpa (6.4 kg/cm 2 ) [90 psi] are not available, the leak can be checked, though still incomplete due to the difference of gas and air, in the method, as shown. The connection between the high pressure hose and the elbow, the tightening torque should be: T = 19.61 ~ 24.52 N m (200 ~ 250 kgf-cm) [14.47 ~ 18.09 ft-lb]... for Brass* T = 27.46 ~ 30.40 N m (280 ~ 310 kgf-cm) [20.26 ~ 22.43 ft-lb]... for Steel* * There are two types of the hose fitting inner valve, i.e. Brass and Steel. The connection of the elbow to the shut-off-valve uses the taper threads. (See points in former paragraph.)

6-7 The connection to the shut off valve for the fuel warning switch (Option). The connection between the shut off valve and elbow, the elbow and the T-fitting, and the T-fitting and the switch use taper threads. (See points in former paragraph.)

6-8 The gas leakage check between the shut-off valve and the regulator with soap water. When checking, leakage A, insert a thin rod through the center hole of the shut-off valve to keep pushing the diaphragm. If the diaphragm is not pushed to open the shutoff-valve, the pressure is not applied to the union A when the engine at cease.

7-2 TROUBLE SHOOTING * Carburetor and air governor mount nuts tightening torque: T = 10.2 ~ 15.3 N m (1.040 ~ 1.560 kgf-cm) [7.524 ~ 11.287 ft-lb]

7-3