83 evinrude 115hp plug fouling

[fsds123]

I have a 1981 Evinrude 115 hp which I have a few questions about. I tried doing a search, but it sucks.

Is it normal for the plugs to foul after a day or two of use? What would cause this. Bad coil packs or wires? Can the wires be replaced by themselves? How long is typical between cleaning/changing plugs?

It runs fine so long as I relace the plugs every few days, but if I don't it gets hard to start/restart. I am using 50:1 with synthetic blend. I also sometimes notice a slight backfire or missing upon starting when the plugs haven't been replaced in a while (few days). I am using the correct plugs, but don't remember the number off the top of my head. (boat is in storage 70 miles from my house)

I did a compression check not too long ago and all cylinders where in good shape within normal limits and close to one another (don't remember the numbers).

Any help/tips would be appreciated.

 

[Walker]

Re: 83 evinrude 115hp plug fouling

What plugs and what gap are you running. What do your plugs look like when they foul

 

[fsds123]

Re: 83 evinrude 115hp plug fouling

What plugs and what gap are you running. What do your plugs look like when they foul

QL77J4 at .040" and they have a wet oily look to them. I do about a 50/50 mix low and high speed boating

 

[tashasdaddy]

Re: 83 evinrude 115hp plug fouling

sound like you are running a little rich. is it running good other than just fouling the plug?. is 1 plug worse than the others? a decarb (engine faq forum) would remove the excess carbon from the cylinders, and will probably help with the fouling. seafoam deep creep, and running the fuel additive in the fuel.

 

[fsds123]

Re: 83 evinrude 115hp plug fouling

sound like you are running a little rich. is it running good other than just fouling the plug?. is 1 plug worse than the others? a decarb (engine faq forum) would remove the excess carbon from the cylinders, and will probably help with the fouling. seafoam deep creep, and running the fuel additive in the fuel.

All plugs are fouling the same, and with clean or new plugs it runs fine. I use the seafoam fuel additive every few tanks, but have not used the deep creep. I'll give that a try next time out. So how long is typical for plugs to stay clean? With gas being $3.00 a gallon spending a couple bucks on new plugs every time out is not a big deal, but it seems a little excessive. (I don't ever replace the plug on 2 stroke lawn mowers for example)

 

[ezeke]

Re: 83 evinrude 115hp plug fouling

New thermostats would probably help.

You will not be able to keep the combustion chamber clean (or the spark plugs) if the motor is running cold.

 

[Dave Abrahamson]

Re: 83 evinrude 115hp plug fouling

Plugs can last years. I only change them out yearly because they're cheap.

 

[tashasdaddy]

Re: 83 evinrude 115hp plug fouling

ezeke has a good point i missed. you can do deep creep using muffs. it just smokes a lot.

 

[fsds123]

Re: 83 evinrude 115hp plug fouling

New thermostats would probably help.

You will not be able to keep the combustion chamber clean (or the spark plugs) if the motor is running cold.

Didn't think of that, could very well be the problem.

Thanks for all the replies!

 

[tashasdaddy]

Re: 83 evinrude 115hp plug fouling

test

 

[fsds123]

Re: 83 evinrude 115hp plug fouling

Just thought of something else...my motor pisses water right away. Is it supposed to, or should it only do so after reaching temperature?

 

[Walker]

Re: 83 evinrude 115hp plug fouling

I'd gap those plugs at .032-.035 and see how she does. I know a lot of guys here like to run .040 but I've always had better all-range performance at .032
Your plugs should be wet looking but not drenched.