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2001 4-Stroke 115 hp EFI mis-fire on 3 and 4
2001 115 hp mercury 4 stroke EFI (SN OT341774)
new injector
new fuel
fuel pressure at 41psi
new spark plugs
new coil on 2 and 3
spark seem weak on cylinder 3 and 4
what I don't understand is 1 and 4 are on the same coil and 2 and 3 are on the same coil. Cylinder 1 and 2 fire fine?????
my understanding is that they both fire on compression and exhaust stroke..
no change i the engine when pulling 3 sparkplug wire off.
any help is appreciated
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Mercury 3L/4 Stroke/Verado Moderator
Compression Test results: ??
Leadown Test Results: ??
Have you placed a timing light on each plug wire, one at a time to confirm your "fire fine" and "weak spark" determinations?
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compression test was 150 and it held
timing light showed spark however, when using a spark tester The spark wouldn't jump the gap. when using a spark plug to ground. Orange weak spark
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Mercury 3L/4 Stroke/Verado Moderator
Could be the plug or the wire.
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I adjusted the throttle shutter synchronization screw and it leveled out.. that changes 3 and 4 cylinder.... smoothed out good.. who knew. maybe that will help someone
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Mercury 3L/4 Stroke/Verado Moderator
May have been the problem- though it's strongly recommended that this be done with a synchronization tool connected so that the adjustment can be made "precisely".