1987 Evinrude 88hp fouling plugs and running rough.

[shotgun33]

I put new plugs in today and it ran great for a while. I took a break for about an hour. When I went back out it ran rough and sorta choppy, but not the whole time. At times it would run smooth at all speeds but most of the time it skipped a lot and it could only go about a third throttle. When i got home I pulled the plugs and one of them was all gray and had what looked like fuel deposits on it.

 

[jalbert34668]

Re: 1987 Evinrude 88hp fouling plugs and running rough.

Fouling plugs look like you dipped your sparkplug in oil , if they look like that you need to check your fuel and oil mixture. If its fouling your plugs theres to much oil in your gas mixture. If your sparkplugs are dry that means you don't have enough oil in your gas mixture causing your motor to run rough and hot!!, Or that cylinder is not getting any fuel! Check these things out.

 

[ezeke]

Re: 1987 Evinrude 88hp fouling plugs and running rough.

If it's only one plug out of four, it's more likely to be a carburetor problem unless it's cylinder #4 in which case it could be a bad fuel pump membrane.

That's if the compression is normal and spark is good.