FUEL SYSTEM Section 3A Electric Fuel Pump Tble of Contents Specifictions........................... 3A-1 Fuel Pump Assembly.................... 3A-2 Specil Tools........................... 3A-3 Fuel Lift Pump Description/Opertion...... 3A-3 Checking for Restricted Fuel Flow Cused by Anti-siphon Vlves....................... 3A-4 Specifictions Checking Fuel Pump Lift (Vcuum)........ 3A-5 Vcuum Test Troubleshooting.......... 3A-5 Testing Fuel Pump.................... 3A-6 Fuel Lift Pump Removl/Disssembly...... 3A-7 Clening/Inspection................... 3A-8 Ressembly/lnstlltion............... 3A-9 3 A FUEL SYSTEM FUEL LIFT PUMP Fuel Recommended Gsoline Recommended Oil Gsoline/Oil Rtio @ Idle @ WOT Fuel Pressure Amperge Drw Gsoline w/oil Injection Unleded 87 Octne Minimum Quicksilver TC-W3 Premium Plus 2 Cycle Outbord Oil 300 400:1 40:1 Norml 1-2 psi (6.8 13.7 kp) Mximum 10 psi (68.5 kp) 1 2 Amperes 90-881986 JANUARY 2001 Pge 3A-1
Fuel Pump Assembly 1 3 2 4 5 6 9 8 7 TORQUE REF. NO. QTY. DESCRIPTION lb. in. lb. ft. N m 1 1 FUEL FILTER 2 1 FUEL LIFT PUMP 3 2 BOLT 145 16 4 2 BRACKET 5 1 BOLT 145 16 6 1 BRACKET 7 1 FUEL/WATER SEPARATOR 8 2 WATER SENSOR 9 1 VAPOR SEPARATOR Pge 3A-2 90-881986 JANUARY 2001
Specil Tools 1. Fuel Pressure Guge (0 15 psi) (Obtin Loclly) 57721 Fuel Lift Pump Description/Opertion The fuel lift pump is n electric fuel pump used to supply fuel to the engine vpor seprtor. b 58740 -Fuel Lift Pump b-fuel Filter Electricl power is supplied to the fuel lift pump from the strter solenoid positive terminl (strter side). 90-881986 JANUARY 2001 Pge 3A-3
Checking for Restricted Fuel Flow Cused by Anti-siphon Vlves While nti-siphon vlves my be helpful from sfety stnd-point, they clog with debris, they my be too smll, or they my hve too hevy spring. Summrizing, the pressure drop cross these vlves cn, nd often does, crete opertionl problems nd/or power-hed dmge by restricting fuel to the fuel pump nd VST. Some symptoms of restricted (len) fuel flow, which could be cused by use of n nti-siphon vlve, re: 1 - Loss of fuel pump pressure 2 - Loss of power 3 - High speed surging 4 - Preignition/detontion (piston dome erosion) 5 - Engine cuts out or hesittes upon ccelertion 6 - Engine runs rough 7 - Engine quits nd cnnot be restrted 8 - Engine will not strt 9 - Vpor lock Since ny type of nti-siphon device must be locted between the engine fuel inlet nd fuel tnk outlet, simple method of checking [if such device (or bd fuel) is problem source] is to operte the engine with seprte fuel supply which is known to be good, such s remote fuel tnk. If, fter using seprte fuel supply, it is found tht the nti-siphon vlve is the cuse of the problem, there re 2 solutions to the problem; either 1) replce the nti-siphon vlve with one tht hs lighter spring tension or 2) replce it with solenoid-operted fuel shut off vlve. Pge 3A-4 90-881986 JANUARY 2001
Checking Fuel Pump Lift (Vcuum) The fuel lift pump is designed to lift fuel (verticlly) bout 60 in. (1524 mm) if there re no other restrictions in the system using fuel hose tht is 5/16 in. (7.9 mm) minimum dimeter. As restrictions re dded, such s filters, fittings, vlves etc., the mount of fuel pump lift decreses. Fuel pump vcuum nd ir bubbles in the fuel supply cn be checked with vcuum guge, t-fitting nd cler piece of fuel hose. Connect the cler hose between the inlet fitting on the pulse driven fuel pump nd the vcuum guge t-fitting; keeping the t-fitting s close s possible to the pump. Connect the fuel line from the fuel tnk to the remining connection on the t-fitting. Before proceeding with the system vcuum test, confirm tht the pulse fuel pump is cpble of supplying the required vcuum. To do this, strt the engine, pinch off/restrict the fuel supply hose between the vcuum guge nd fuel tnk. The vcuum guge should rise to or exceed the mximum norml reding of 2.5 inches vcuum (mercury). If it fils to rech this minimum number, the pump needs servicing or there is lck of crnkcse pressure to operte the pump. c b -Cler Hose b-t-fitting c -Vcuum Guge Vcuum Test Troubleshooting 57721 This test is normlly performed t n idle speed. As engine rpm increses, there will be slight increse in vcuum. The increse should not exceed specifiction. Norml Reding Below 2.5 in. of vcuum (mercury) Reding bove 2.5 in. of vcuum (mercury) Restriction within the fuel system Restricted nti-siphon vlve Restriction within the primer bulb Kinked or collpsed fuel hose Plugged wter seprting fuel filter (in the bot) Restriction in fuel line thru-hull fitting Restriction in fuel tnk switching vlves Plugged fuel tnk pick-up screen 90-881986 JANUARY 2001 Pge 3A-5
Testing Fuel Pump Instll cler fuel hose(s) between fuel pump nd VST. Run engine, nd inspect fuel pssing thru hose(s) for ir bubbles. Problem: Air Bubbles in Fuel Line Low fuel in tnk. Fill tnk with fuel. Loose fuel line connection. Check nd tighten ll connectors. Fuel pump fitting loose. Tighten fitting. A hole or cut in fuel line. Check condition of ll fuel lines nd replce Fuel Pump nchor screw(s) loose. Tighten ll screws evenly nd securely. Fuel Pump filter cover nchor screw loose. Tighten screws securely. Fuel pump filter gsket worn out. Replce gsket. Fuel pump gsket(s) worn out. Rebuild fuel pump. Fuel vporizing Fuel with high reed vpor pressure (winter grde fuel) my vporize (form bubbles) when used in hot/wrm wether. Use fuel with lower reed vpor pressure (summer grde fuel) Problem: Lck of Fuel Pump Pressure An nti-siphon vlve. See Checking for Restricted Fuel Flow preceding. Air in fuel line. See Air Bubbles in Fuel Line, bove. A dirty or clogged fuel filter. Clen or replce fuel filter. The fuel pickup in fuel tnk is clogged or dirty. Clen or replce pickup. Worn out fuel pump diphrgm. Rebuild fuel pump. Worn out check vlve(s) in fuel pump. Rebuild fuel pump. A leky check vlve gsket. Rebuild fuel pump. Pulse hole(s) plugged. Remove fuel pump nd clen out holes. Hole in pulse hose. Replce pulse hose. Loose pulse hose. Tighten connection(s). Fuel hose internl dimeter too smll. Use 5/16 I.D. fuel hose. Excessive fuel lift required. Fuel lift exceeds 2.5 in. of vcuum (mercury) Pge 3A-6 90-881986 JANUARY 2001
Fuel Lift Pump Removl/Disssembly 1. Disconnect fuel pump hrness connector. 2. Disconnect fuel hose from fuel filter. 3. Use shrp side cutter or end cutter to peel bck end of clmp securing vpor seprtor hose. Remove hose from fuel pump. 4. Loosen bolt securing pump retining clmp nd remove pump. d c 58732 b e -Hrness Connector b-fuel Hose c -Clmp d-bolt e -Fuel Pump 58740 90-881986 JANUARY 2001 Pge 3A-7
Clening/Inspection There re no serviceble prts within the electric fuel pump. However, there is replceble fuel filter on the pump which should be replced every 100 hours or once seson. Use strp wrench to remove filter. -Fuel Filter Pge 3A-8 90-881986 JANUARY 2001
Ressembly/lnstlltion ASSEMBLY 1. Instll fuel pump inside retining clmp. Secure clmp with screw. Torque screw to 145 lb. in. (16.0 Nm) 2. Reconnect hrness connector. 3. Reconnect fuel tnk hose to filter. Use stinless hose clmp to secure fuel hose. 4. Reconnect vpor seprtor fuel hose to fuel pump. Secure hose with clmp #183. Use Clmp Tool 91-803146T to secure clmp. 5. Run engine nd check for leks. f d c 58732 b g e -Fuel Pump b-stinless Hose Clmp c -Hose Clmp #183 d-screw Torque to 145 lb. in. (16.0 Nm) 58740 e -Hrness Connector f -Fuel Hose g-filter 90-881986 JANUARY 2001 Pge 3A-9