Spark Plug Fowling

Mon Apr 19, 2004 7:40 am

Hi all!

I have a question about spark plugs. It seems as though I am forever having to clean my spark plugs. After even only a day or two of plowing, enough carbon builds up that starting is either difficult or impossible. I reset my gap every time.

Any Ideas????


Mon Apr 19, 2004 8:06 am

Don't know what plugs you are using, but I prefer the Cahmpion D21 plugs. They are a hotter heat range and don't seem to foul as much. Also in my personal opinion, using a mid range (silver) gas seems to also reduce fouling.

Mon Apr 19, 2004 8:29 am

Try a hotter plug like John said and also the cub has no tstat to warm the engine in cooler weather. During the cool and cold month ( for snow plowing) I use a large garbage bag to block the grill to get the engine temp up. A couple clothes pins around the headlight post keep it in place. In winter I completly cover the grill and after alot of checking the coolant level it still has never reached the level it runs while mowing in the summer with the grill clear.

Mon Apr 19, 2004 9:32 am

I've had the same problem in the past. Can't say this will fix but ACDelco makes a hotter plug yet. P/N C87. Try that and high octane fuel.There still is a mystery here because some folks have the problem and some don't.

Mon Apr 19, 2004 10:13 am

There still is a mystery here because some folks have the problem and some don't.

Too rich a mixture adds to the problem, as does extended idling. While the Cub's carburetor has no direct high speed mixture control, lowering the float level will have a leaning effect. A restriction in the air cleaner will also cause a rich mixture. Service the air cleaner!