4 cyl engine 2 cyl. no fire

realmenpray

Recruit
Joined
Sep 6, 2010
Messages
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I have a 1991 Johnson 120 VRO and I have lost 2 cylinders from fireing both on the same side
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 4 cyl engine 2 cyl. no fire

Look up the wiring diaghram and see if the overheat sensor is connected to the powerpack. If so, you have the SLOW systems that kills the spark to 1/2 the motor, if it overheats. You should be able to disconnect the overheat sensor and see if spark returns.

If that isn't it, get a manual, and troubleshoot the powerpack in question.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 4 cyl engine 2 cyl. no fire

I may be wrong but I was always taught that when the mtr went into slow the pack would make all the cylinders miss fire, not just one bank and if you kept running it there (which you didn't want to do) the worst that could happen is you would foul out the spark plugs. Anyway, the best thing to do here is to get an OEM service manual, a peak reading volt meter and check out the ignition system. Possible you have a bad power pack or coils. May want to swap coils from side to side and see what happens. Also check out all your ground connections on the coils and power pack.
 
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