2-cycle spark plug fouling

Tdog · Jun 5, 2006

I have a Craftsman weedeater that accepts attachments - - besides the string trimmer, I have a pruner & a tiller attachmet. I used the pruner quite a bit today & it works pretty well, except the spark plug kept fouling. I'd pull the plug out & clean it - then it would run fine for a while. Till the nex time it happened. You could pull & pull, but it would not start. Must have cleaned the plug 3-4 times.
Any idea what causes this? Is the mixture too rich? I don't have a lot of experience with fixing small [or large!] engines. Wonder if my gas/oil mixture has too much oil? I know I aimed for a 50:1 mix.

Thanks, Jack

Tdog · Jun 5, 2006

I have a Craftsman weedeater that accepts attachments - - besides the string trimmer, I have a pruner & a tiller attachmet. I used the pruner quite a bit today & it works pretty well, except the spark plug kept fouling. I'd pull the plug out & clean it - then it would run fine for a while. Till the nex time it happened. You could pull & pull, but it would not start. Must have cleaned the plug 3-4 times.
Any idea what causes this? Is the mixture too rich? I don't have a lot of experience with fixing small [or large!] engines. Wonder if my gas/oil mixture has too much oil? I know I aimed for a 50:1 mix.

Thanks, Jack

beenthere · Jun 5, 2006

Maybe the "aim" was not good. Don't know how you mixed it, but I'd dump it and start with fresh. I mix a gallon at a time and only use the small bottles that are sized for one gallon.

Also, I'd look at the muffler, and see if it is also clogged with soot and carbon and burned oil debris. If they clog up, then things don't run well. Check the air filter, which I assume you already have.

Get gas without the ethanol and the higher octane than the low price gas. All should help. If you haven't bought a new plug, get one and don't let it be a Champion. They don't have a very good track record for quality anymore, from all that I hear.

Good luck. Nothing more frustrating than a two-cycle that wont run right.

Just another thought, do you run it wide open? or at slow rpm which will plug them up quick.

beenthere · Jun 5, 2006

Maybe the "aim" was not good. Don't know how you mixed it, but I'd dump it and start with fresh. I mix a gallon at a time and only use the small bottles that are sized for one gallon.

Also, I'd look at the muffler, and see if it is also clogged with soot and carbon and burned oil debris. If they clog up, then things don't run well. Check the air filter, which I assume you already have.

Get gas without the ethanol and the higher octane than the low price gas. All should help. If you haven't bought a new plug, get one and don't let it be a Champion. They don't have a very good track record for quality anymore, from all that I hear.

Good luck. Nothing more frustrating than a two-cycle that wont run right.

Just another thought, do you run it wide open? or at slow rpm which will plug them up quick.

HammerFour · Jun 6, 2006

Possibly to much oil in the mix, or to rich of a carburetor setting...or just idling to much will foul a two stroke plug pretty easily.

If you have to let it idle more than 15 seconds, shut it off.

HammerFour · Jun 6, 2006

Possibly to much oil in the mix, or to rich of a carburetor setting...or just idling to much will foul a two stroke plug pretty easily.

If you have to let it idle more than 15 seconds, shut it off.