99 Johnson V-4 90hp

Flat-Out

Cadet
Joined
Feb 13, 2005
Messages
6
Hey guys, new member here. My motor is skipping somtime at high rpm's 4000-5000.It runs fine at idle or slow speeds,I thought it might be water in the fuel tank or maybe the plugs? I removed the plugs and inspected them and they look Ok? They are gapped at .030, I have read in the forum that OMC's should be gapped at .040 ? The Champion brand I use is L78YC. Is this the correct plugs? I will change plugs and test run and possibly install a water/fuel separator. This motor has been flawless, any advise will be welcomed.
 

muskrat

Chief Petty Officer
Joined
Apr 13, 2004
Messages
445
Re: 99 Johnson V-4 90hp

IF IT HAS VRO YOU SHOULD USE QL78YC,BECAUSE IT WILL INTERFERE WITH IGNITION SYSTEM
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: 99 Johnson V-4 90hp

Muskrat is right about using the Q plugs but you have a oil injection system, not a VRO system. Just wanted to clarify that. You can also use the QL77JC4's. Great motor.
 
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