Outboard Systems. Section 7 Precision Blend

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1 Section 7 Precision Blend THEORY OF OPERATION MECHANICAL OIL PUMP Pump Operation PBS WARNING SYSTEM Three LED Lamp System Three LED Troubleshooting Oil Level Warning Lamp Assembly Check Oil Tank Sensor Check PBS Electrical Problems V-6 Oil Transfer System Components & Basic Operation LAB EXERCISES Oil Transfer System V-6 HPDI Oil Level Sensor Lab PBS Simulator

2 Precision Blend Theory of Operation In the past, all two-stroke outboard motors required the oil and gas to be mixed in the gas tank. This was the only way to lubricate the engine. This premix system, while simple, has several drawbacks. The boat owner has to remember to mix the oil and gas which can be a complicated and messy proposition. The proper ratio is also important. If the owner mixes the wrong ratio or forgets the oil entirely and runs straight gas, the engine could be damaged. Even when the oil is mixed at the recommended ratio, that ratio is only correct for one narrow rpm band. An engine might need as little as 200:1 at idle and as much as 50:1 at wide-open throttle. The premix ratio must be set to the richest mixture needed to be safe. But that means that the engine can get four times as much oil as necessary at idle. This tends to foul plugs and produce excessive smoke. The Precision Blend Oil Injection System (PBS) used by Yamaha solves many of the premix problems. At the heart of the system is a precision mechanical oil pump. This pump is driven by a shaft connected to the crankshaft. As engine rpm changes, so does the output of the oil pump. The oil pump responds not only to engine rpm, but also to throttle opening. The oil flow control lever on the oil pump is connected to the carburetor throttle shaft. As carburetor opening changes, so does pump stroke. Oil delivery increases as rpm and the throttle opening increase. By adjusting the amount of oil the pump delivers to match engine-operating conditions, overall oil consumption and smoke are reduced. Oil Flow Control Lever Crankshaft Oil Outlet Direction of Rotation Oil Injection Pump Pump Drive Shaft (Worm Wheel) Driven Gear Drive Gear (Worm) 7-2

The oil feed lines from the pump go directly to the intake manifold, except OX66 models. Placing the oil lines here makes delivery of oil into the engine almost immediate.

The fuel is put in one tank and oil in another. Additionally, a warning system has been provided to alert when the oil level gets low.

3 The oil feed lines from the pump go directly to the intake manifold, except OX66 models. Placing the oil lines here makes delivery of oil into the engine almost immediate. This is particularly important when the amount of oil required changes, such as when the throttle is opened abruptly. The Precision Blend system offers relief from premixing fuel and oil. The fuel is put in one tank and oil in another. Additionally, a warning system has been provided to alert when the oil level gets low. A sensor monitors the oil level and when the level is low, a warning light is activated and rpm is reduced to Activation of systems depends on equipment used and the rpm of the engine. To prevent unexpected acceleration if oil is added during operation, a hold circuit is built into the PBS system. Once the rpm reduction has been activated, the system must be reset to bring back full rpm operation; the rpm will not automatically increase even after the oil tank is refilled. To reset the hold circuit, you must return to neutral and, depending on the ignition control unit s circuitry, cycle the key off and on again after refilling the main oil tank. Oil Level Warning Lights (Electric Starting Model) Oil Level Warning Lights (Manual Starting Model) Oil Level Warning Lights (Electric Starting Models) Buzzer Top Cowling Oil Tank Cap Oil Tank Fuel Tank Battery Oil Level Sensor Control Unit Oil Injection pump MECHANICAL OIL PUMP The key component in any oil injection system is the oil pump. Over the years, Yamaha has used two different manufacturers for the oil injection pumps. Keihin pumps were used from 1984 ~ These pumps have built-in check valves and rotate counter-clockwise (CCW). If the Keihin pump fails, it is not repairable. Mikuni makes the replacement pumps. The replacement pumps are available as kits, with separate check valves to be inserted in the output oil lines, and a mounting adapter for the replacement pump. Refer to Service MIKUNI OIL PUMP 7-3

4 Bulletin for the applicable part numbers. Some Mikuni pumps rotate clockwise (CW), and some rotate CCW (CCW pumps have a "09" stamped on the control lever). After 1988, Mikuni supplied oil pumps for inline engines. In 1989, Mikuni began supplying pumps for all Yamaha oil injection outboards. The Mikuni engines do not have built-in check valves, and rotate CW. A separate check vale must be installed in the oil hose(s) between the pump and intake manifold. Pump Operation The oil pump drive gear is pressed onto the lower end of the crankshaft, and drives the input or worm shaft of the oil pump. The worm gear and shaft drive the plunger cam of the oil pump. As the plunger cam rotates, it moves up and down while riding on the pump lever shaft. With this movement, oil is pumped. The position of the plunger and the pump lever shaft controls the oil output. Check valves in the oil delivery lines or pump prevent siphoning of oil from the oil tank to the intake. The check valve also prevents any back flow from the delivery hoses. The position of the throttle controls the position of the plunger cam. This, in conjunction with engine speed, controls the amount of oil injected and the fuel-to-oil ratio. Depending on the engine, this ratio can vary from 200:1 at idle, to 30:1 at wideopen throttle (HPDI). THREE LED LAMP SYSTEM This system uses three LED lamps to indicate the amount of oil left in the injector tank. The control unit and lamps are located either on the engine pan or in a gauge. This system is used on many of the 40hp and 50hp three-cylinder models. The oil tank is located underneath the PBS THREE LED SYSTEM R Y G 7-4

5 cowling on the side of the power head. The three lamp colors are green, yellow, and red: Green indicates a full to near-full tank of oil. Yellow indicates that about a third of the tank of oil is remaining. Red indicates that the tank has less than 10% oil remaining. When the red lamp comes on, the rpm reduction is switched on and the warning buzzer sounds. The primary components of this system are: The tank sensor LED lamp assembly Control unit The 1994 and earlier three-led systems require battery voltage to operate. Beginning in 1995, the yellow/red wire from the CDI has powered the system, so no battery is required. The tank sensor has two built-in switches. One switch is located near the top of the sensor shaft. This upper switch is SW1. The other switch is located near the bottom. This lower switch is SW2. One side of each switch is connected to ground through the black wire. The other end of the upper switch (SW1) is connected to a green wire. The other end of the lower switch (SW2) is connected to a green/red wire. When the oil tank level is over 30% full, the sensor s magnetic float closes the circuit on SW1. This completes the circuit between ground and the green wire. The control unit receives this signal and turns on the green LED lamp. As oil is consumed, the oil level drops in the tank. The sensor float drops with the oil lev- SW.2 ON SW.1 ON 7-5

6 el. When the float reaches a point when SW1 opens and SW2 is open, neither switch is closed. The control unit responds by shutting off the green lamp and turning on the yellow lamp. If the oil level continues to drop, the sensor float will drop down and close SW2. This completes the circuit between the green/red wire and ground. When the control unit gets this signal, the yellow light is turned off and the red light is turned on. The green/red wire from the oil tank sensor is also connected to the pink warning wire. This also activates the warning system including rpm reduction to 2000 rpm. This rpm reduction will only occur if the engine is being operated above 2000 rpm. This system also uses a hold circuit to prevent a sudden return to a previous throttle setting. This circuit won t allow the engine to return to full throttle operation with the warning on until the ignition is cycled off and then back on. This resets the system. The hold circuit is built into the tank sensor under the cap. Most of these tank sensors will have an H stamped on the top of the cap to identify them. The 90hp may or may not have an H stamped on the top of the oil level sensor. However, these units all have a hold circuit built into them. Three LED Troubleshooting and Earlier There are basically two parts to this system: Oil tank sensor Lamp/control unit (the lamp assembly and the control unit come only as an assembly). Begin troubleshooting by identifying the problem. First, be sure the problem is with the PBS system. This system requires a 7-6

7 battery in good condition. Check out the battery before testing the electronics. Also don t forget to check the grounds on the system. Make sure the yellow wire to the control unit has 12 volts and the black wire is grounded. Total failure or dim lights (high resistance) can be a symptom of bad grounds. Lamp/Control Unit Check 1. Disconnect the sensor and turn the power on. The control unit is getting an open circuit to the sensor, so the yellow lamp should come on. 2. Ground the green wire. The green lamp should come on. 3. Ground the green/red wire. The red lamp should come on. If these tests give the correct readings, the control unit and lamps are OK. A failure of one or all the lamps will require replacement of the control unit/lamp assembly. If the lamps are OK, test the oil tank sensor. Oil Tank Sensor Check Isolate the sensor from the rest of the system. Test the sensor assembly using a digital multi-meter set to the diode test position. 1. Connect the negative (black) meter lead to the black lead from the sensor. Connect the positive (red) meter lead to the green (SW1) sensor lead. When the float is up, closing SW1, the meter should show continuity. When the float is down, the meter should show an open circuit. 2. Before checking SW2, position the float so that neither switch is closed. Now connect the red meter lead to the green/red sensor lead. The meter should indicate an open circuit. Now position the float all the way to the bot- 7-7

8 tom of its travel, closing SW2. The meter should now indicate less than 1 volt (~.5 volts). This means the switch has closed. 3. With the meter still connected, move the float up, opening SW2. This sensor has a hold circuit and the meter should remain the same (~.5 volts), until one meter lead is disconnected. If the reading does not hold, the sensor is defective and Later This system is similar to the 1994 and earlier system. This PBS system contains: Oil tank sensor assembly Oil level warning lamp assembly The oil level sensor has an additional pink lead that connects to the warning horn and the CDI for rpm reduction. If the pink lead from the oil level sensor should become broken or disconnected, there would be no rpm reduction or warning horn. The oil lamp assembly contains three LEDs that operate on low voltage. The warning lamp assembly receives its power directly from the CDI. The engine must be running for the warning lamps to operate. Before any troubleshooting, first check all ground connections. Oil Level Warning Lamp Assembly Check To test the oil level warning lamp assembly, connect two 1.5-volt flashlight batteries in series. Use 3 volts maximum for testing. 1. Connect the yellow/red lead to the positive terminal of one battery and the black ground wire to the negative terminal of the other battery. Be sure to observe polarity or the lamp assembly 7-8

9 will not function. You should have a yellow lamp. 2. Ground the green wire to the black wire. The yellow lamp should turn off and the green lamp turn on. 3. Ground the green/red wire to the black wire. The yellow lamp should turn off again and the red lamp turn on. If one of the lamps fails to light up, replace the complete lamp assembly. If the lamps are OK, test the oil tank sensor. Oil Tank Sensor Check The oil level sensor (on 1995 and newer models) is tested the same as on previous models. It has the same switches and hold circuit as the models discussed earlier. PBS Electrical Problems This system switches control leads to ground. If you have a short-to-ground on either a control lead to the sensor or on a sensor lead, the control unit will think a switch is closed. Watch for pinched wires. Check color codes and watch out for incorrect connections. V-6 Oil Transfer System Components & Basic Operation This is Yamaha's most advanced PBS system. Larger motors consume more oil and an engine mounted oil tank by itself would not have sufficient capacity to satisfy customer demand, or would be so large as to take up excessive space and add additional weight to the engine. A large remote tank is included in this system to supply oil to the smaller, engine mounted oil tank under the cowling. Oil is pumped from the remote tank to the engine tank using an electric transfer pump. 7-9

Remote Oil Tank The remote oil tank (boat mounted) holds approximately 11.1 quarts or 2.8 gallons of oil. An optional 5 gallon oil tank for extended range or larger boats is also available.

10 Remote Oil Tank The remote oil tank (boat mounted) holds approximately 11.1 quarts or 2.8 gallons of oil. An optional 5 gallon oil tank for extended range or larger boats is also available. The tank has a filter between the outlet side of the tank and the transfer pump. The transfer pump fits in a recessed area of the remote oil tank and is powered by the engines battery. The tank also contains an oil level sensor to detect the level of oil in the tank. Engine Oil Tank The engine oil tank is mounted under the engine cowling and has a capacity of approximately 0.95 quart. Oil flows from the tank to the engine driven oil pump by gravity. This tank also has an oil level sensor assembly. Engine Oil Tank Oil Level Sensor This sensor detects the level of oil in the tank and signals the oil control unit. The sensor consists of three reed-type switches known as SW1, SW2, and SW3 works much like the oil level sensor discussed on the three lamp system). These switches control the transfer of oil from the remote tank and activate the no oil warning system. A float containing a magnetic ring travels up and down the sensor shaft as the oil level changes. The magnet in the float causes the switch to close when it comes close to it. As the float moves past the switch, the switch returns to the open position. The color codes for the engine tank switches are as follows: 7-10

11 Checking Engine Tank Oil Sensor To check SW1 on this sensor assembly, set your DMM to the diode test position. Use clips or a jumper and connect the black meter lead to the black wire to the sensor, and the red meter lead to the blue/white wire. With the float at the top of the shaft (SW1 closed), the meter should show continuity. Move the float down (SW1 open) and the meter should show O.L. To check SW2, connect the meter red lead to the blue/green lead. Move the float from top to bottom and the meter should indicate O.L. - continuity - O.L. To check SW3, connect the red meter lead to the blue/red. Move the float from top to bottom and the meter should indicate O.L. and then continuity when the float contacts the bottom of the shaft. Remote Tank Oil Level Sensor This sensor contains a single reed-type switch, referred to as SWB, mounted low on the sensor shaft with black and black/red wire leads. When the multi-function tachometer is used, all three LCD indicators will be displayed when the float is closed or the float is up, indicating a full to near full condition in the oil tank. When the switch is open or the float is down, the right side LCD indicator will go out, the middle LCD indicator will flash (indicating a low oil condition) and the left side LCD indicator will stay solid. Also, with the float down, the control module will stop the automatic transfer of oil to the engine oil tank. 7-11

12 Checking Remote Oil Tank Sensor Set the meter to the diode test position. Using clips or a jumper, connect the red meter lead to the Black/Red lead of the sensor, and the black meter lead to the black lead of the sensor. With the float at the top of its travel the meter should show continuity, indicating SWB is closed. When the float drops to the bottom of its travel, the meter should now show O.L. indicating SWB is open. Oil Level Sensor Operation with Multi-function Tachometer If both of the oil tanks are full of oil, both of the floats would be to the top of their travel. If a multi-function tachometer is used, all three LCD indicators would be displayed. The engine will use oil from the engine mounted tank first. As the oil level drops, SW1 will open. The engine will continue to operate normally, no warnings or indicators. As the oil level continues to drop, the float will now close SW2. At this point, the transfer pump will turn on and oil will be pumped from the remote tank to the engine tank. When the tank is full, SW1 will now close, shutting off the transfer pump. This system will only transfer oil if the engine is running (except for initial service). During the automatic oil transfer process, the oil in the remote tank will continue to drop. If oil is not replenished in the tank, eventually the float will drop down and open SWB. At this point, the automatic transfer of oil will stop, and the tach will indicate a low oil condition by having the middle LCD indicator flash, while turning off the right side indicator. The engine will continue to run normally without any other warnings or indicators. DIGITAL TACHOMETER Full or Near Full / SWB closed / SW3 open DIGITAL TACHOMETER Low Oil / No auto oil Transfer / SWB open / SW3 open 7-12

13 When SWB opens, the remote tank will still contain approximately 2 quarts of oil, but can only be transferred to the engine tank two times by the emergency switch located on the powerhead. If the engine continues to run without re-filling the remote tank, the oil level will continue to drop in the engine oil tank, and eventually will close SW3. A warning horn will sound, the tach will flash the left side LCD indicator, indicating No Oil and the engine will go into rpm reduction, not allowing the engine to operate above 2000 rpm. DIGITAL TACHOMETER No Oil / Warning Horn / Reduced rpm / SW3 closed Warning Reset V-6 HPDI To reset the warning system, tachometer LCD, warning horn, and RPM reduction, the control must be returned to the neutral position (or less than 1200 rpm) and SW3 must be opened. Opening SW3 may be done in one of two ways. Oil may be transferred manually as previously mentioned, or oil can be added to the remote oil tank and transferred automatically. For these engines, it is not necessary to cycle the key off and on. If oil is added to the remote oil tank, SWB will close first and the three LCDs in the tach will flash until enough oil is transferred to open SW3 in the engine oil tank. When SW3 opens, the engine may be returned to normal operation. Should oil NOT transfer from the remote oil tank, even though it has sufficient oil to keep switch SWB closed, the oil level will drop in the engine oil tank. When the oil level drops low enough to close SW3 in the engine oil tank, the warning horn will sound, the engine RPM will be reduced to 2000 rpm, and all three LCD indicators will flash in the tachometer. 7-13

14 The failure of oil to transfer with SWB closed can be caused by a plugged remote tank oil filter, a failed oil transfer pump, or a failed signal to the oil transfer pump. Oil Pump Bleeding Procedure (All HPDI) 1. Disconnect the oil control rod and insure the oil pump control arm is in the full open position. Also, be sure the engine oil tank contains ample oil. 2. Remove the bleed screw and gasket on the oil pump and allow air to purge for a minimum of one minute, longer if necessary. 3. Once solid oil flows, re-install the bleed screw and gasket and secure. 4. Remove the propeller and propeller hardware. Start the engine and run it only at idle. 5. Place it into forward gear, so it is running on all 6 cylinders. Open the bleed screw on the oil pump and re-verify that all air has been purged. Close and secure the bleed screw. 6. Allow it to idle for a minimum of 10 minutes. This is to ensure that there is ample crankcase lubrication prior to placing a load on the unit. 7. The unit should show smoke out of the exhaust at this time. Shut the unit off and re-install the oil control rod on the oil pump control arm and verify proper 0.1 ~ 0.5mm adjustment 8. Install the propeller and torque it to specifications. Install the cotter key. 7-14

15 70hp & Smaller (no bleed screw) 1. Remove oil control rod. 2. Idle engine, watch for clear hoses to fill. 3. Re-install and adjust oil control rod per Service Manual. 90hp & Larger (except OX66 and HPDI) 1. Remove the oil control rod. 2. Idle the engine. 3. Open the bleed screw, bleed air, and close bleed screw. 4. Watch for clear hoses to fill. 5. Re-install the oil control rod and adjust for minimum oil output at idle. OX66 Models 1. Idle engine. Do not remove oil control rod! 2. Open bleed screw, bleed air, and close bleed screw. 3. Verify all oil delivery hoses are full. 4. Stop engine and adjust oil control rod for minimum oil output at idle. NOTE: The recommended oil is YamaLube 2M. If this oil is not available, then another NMMA Certified TC-W3 oil may be substituted. 7-15

ELECTRONIC FUEL INJECTION

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