1994 9.9 evinrude skipping

[rebars1]

1994 evinrude 9.9 E10RELERB. When running on plane, one cylinder will drop out for awhile, then kick back in (runs fast-slow-fast-slow). At idle it runs OK but a bit rough, with the motor wiggling around a bit. I have replaced the plugs, power pack, and coil but no real change. Any ideas for a fix?

 

[rebars1]

Re: 1994 9.9 evinrude skipping

Does this sound like a fuel problem or an ignition problem?

 

[lexkyboater]

Re: 1994 9.9 evinrude skipping

Seems that plug wires are a prevailing problem there. That was a problem on my 71 Johnson 9.5 HP. When you replaced the coils, you really need to check resistance on the plug wires and wiggle them to make sure there's no opens. Those wires take a lot of abuse moving back and forth as the throttle is turned and timing advances. They flex a lot and if haven't been replaced in a while, should be replaced when coils are changed out. On mine, I changed out the coils, but was checking resistance of the wires, thought I had a bad connection, wiggled it then got 0 resistance, wiggled again and dropped to infinite. Aha!

 

[rebars1]

Re: 1994 9.9 evinrude skipping

Thanks for the response. I'll give it a try.

 

[iwombat]

Re: 1994 9.9 evinrude skipping

You've only got one carb servicing both cylinders. With that in mind, one jug dropping in and out will 99% of the time be an ignition problem. Plug wires are a good bet.

 

[OptsyEagle]

Re: 1994 9.9 evinrude skipping

My 1975 9.9Hp Evinrude was doing that on and off again, but after a while the one cylinder would seem to drop out for good and WOT would give me about a trolling speed.

I did a few things to determine that it was spark related and then I changed my spark plugs from Champions to NGKs and the problem went away. At first I figured that perhaps I had one bad Champion plug (although it was brand new) but now I am leaning towards the fact that perhaps I am not torqueing them enough and that the NGKs just allow for a little less torque than the Champion spark plugs.

Since my motor is running like a top, I have not had the ambition to figure this one out. Just darn glad that the surging and then slowing and then surging then slowing has gone away. Good luck to you.