Fouled Plug

[lockman1]

Originally Posted by RRT74

Hey lockman, how often should you use seafoam and how much. I have a 92 carryall btw.

I use Seafoam year-round in all of my small engine fuels,
Per the directions... it's 1 ounce to 1 gallon of fuel, I use about 1-1/2 to 2 ounces per gallon.
Just a little added protection, and not too much to make it/them run poorly!

[RRT74]

Thanks for the much needed information

[zombiehunter]

what gap for the spark plug?

[Cruise Master]

Originally Posted by tenn red

..snip.. I adjusted carb. 1 1/2 turns out on mixture screw. Any ideas on what might be wrong ?

Normally that makes the mixture richer which would cause more carbon buildup (that black stuff you're talking about.)

Old school way to adjust it is to very lightly spray carb cleaner above the intake (not into it.) if the engine speeds up then you're lean, if no effect then rich (turn the screw in.) Once you hit the sweet spot, then turn the screw out about 1/8'th to 1/4 turn. If you run too lean you can fry a piston top.

[lockman1]

Originally Posted by zombiehunter

what gap for the spark plug?

.027 to .031

[Shepard]

Outside of the carburetor being a little rich an other reason for a mysterious black spark plug is a failing ignition system, stilling operational but weak in spark voltage. Check all your other causes and if there is none. Check your ignition system.