Mariner Mercury 105/140 JET, Service Manual

Page: 298 / 797

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Perform all preliminary checks page 3D-14.
•
Adequate fuel pressure (34 to 36 psi; 234 to
248 kPa) follow Low/High Fuel Route Flow
Charts.
•
Place outboard in water or on flush attach-
ment (P/N 44357A2) run engine speed be-
tween 2000 and 2500 RPM.
No RPM change on cylinder(s),
indicating problem in cylinder(s). RPM decreases (on each
cylinder).
Perform Injector Electrical Har-
ness Test (page 3D-34). Fuel delivery OK.
Broken circuit to injector. Injector circuit tests OK.
Perform Induction Manifold Dis-
assembly and inspection (page
3D-55/60). Perform Injector Fuel Delivery
Test (page 3D-34).
RPM increase occurs. No RPM change.
Perform induction manifold dis-
assembly. Inspect injector and
filter. Perform compression check on
problem cylinder see section “1”.
Low or no compression on cylinder. Compression OK.
Inspect cylinder bore. Refer to
Section 4 for disassembly.
NOTE: Injector filters must be
inspected prior to reassembly.
Check 1) Damaged reeds
2) End cap seals
3) Crankcase split line leak
4) Crankshaft sealing rings
Results Results
Results
Results
Results
Results
Results Results
With engine running (2000-2500 RPM) remove
spark plug leads one at a time using insulated
pliers.
90-824052R3 JUNE 2002 FUEL SYSTEMS - 3D-25
Fuel Rail Electrical/Fuel Determination