Lower Spark plug keeps fowling out

[Beau900Dowdy]

I have an 80 hp merc that the lower spark plug keps fowling out. I have very limited automotive experiece...enough to change the plugs...but no outboard experience (until now)

I can change itone day and it is fowled the next and is causing a serious miss,but works great for the first trip after the new plug is installed.

CAN ANYBODY HELP?????

 

[Barnacle_Bill]

Re: Lower Spark plug keeps fowling out

Have you done a compression check?

 

[Chris1956]

Re: Lower Spark plug keeps fowling out

Is the plug fouled with fuel or water? If fuel, you need to check the lower carb float and inlet needle for proper adjustment and operation. Sometimes the floats get saturated with fuel, or the little spring on top of the float rusts away. Alternatively, your fuel pump may have a leak in the diaphram.

If it is fouled with water, you may have a bad lower crank seal or water jacket leak.

 

[freddyray21]

Re: Lower Spark plug keeps fowling out

could also be weak spark to that plug.

 

[Beau900Dowdy]

Re: Lower Spark plug keeps fowling out

Compression about 97, the fouling seems to be oil/fuel...it is actually depositing carbon on the spark plug. Fuel filters replaced and new gas and an injector cleaner ran through. Starts everytime, but after a trip up the lake and turned off, it starts to miss and seems not to have any power.

I will try the fuel pump. Is this something I can do myself?

 

[andy6374]

Re: Lower Spark plug keeps fowling out

What is the compression on the other cylinders?

Have you verified that that particular cylinder is firing?