Mariner Mercury 105/140 JET, Service Manual

Page: 314 / 797

90-824052R3 JUNE 2002 FUEL SYSTEMS - 3D-41
Problem Diagnosis
Condition Possible Source Action
Engine Down On Power Or RPM – Failed Switch Box
– Failed Stator
– Failed Coil
– Low Compression
– Broken Reed
– Fuel Delivery Problem
– Manifold Fuel Leak
– Model 200 only – Detonation
Control System Activated Or
Failed.
– Vapor Separator Flooding Over,
Engine Running Rich.
– Cylinder Head Temperature
Sensor Circuit Failed.
Refer to Section 2A Electrical and
Ignition Tests.
Refer to Section 2A Electrical and
Ignition Tests.
Refer to Section 2A Electrical and
Ignition Tests.
Refer to Section 4A Power Head.
Perform Injector Fuel Delivery
Test (page 3D-34)
Follow Low/High Pressure Fuel
Route Flow Charts and Fuel Rail
Electrical/Fuel Determination Flow
Chart.
Perform Induction Manifold Leak
Check (page 3D-36).
Perform Detonation Control Mod-
ule Check (page 3D-38).
Check for fuel coming out of vapor
separator vent hose.
Check cylinder head temperature
sensor (page 3D-37).
Poor Acceleration – Idles Ok, Top
Speed Ok – Improper EFI Set Up.
– Water Covering Idle Relief
Exhaust Ports.
– T.P.S. Failure.
– MAP Sensor Failure
– R.F.I. Problem*
– Timing Not Advancing.
Refer to Section 2A Electrical and
Ignition for proper EFI set up pro-
cedures.
Boats with extended transoms or
low engine mount can cause en-
gine to load up on acceleration.
Refer to Electronic Fuel Injection
Tester Manual 91-11001A2.
Refer to Electronic Fuel Injection
Tester Manual 91-11001A2.
Install BUZ8H Spark Plugs.
Check for stuck trigger.