Expert: Allen Kirkland - 6/13/2006

Question
Hi Allen,
I just took the mufler off my craftsman lawnmower and there is carbon build up. That's why I guess the lawn mower is not working the way it's supposed to. I just to know how I go about cleaning out the carbon build up in the exhaust port and the mufler.

Answer
Hi Randy
Randy- if this isn't a two-stroke mower engine (where you have to mix oil and gas) forget about the carbon build-up.  Four-cycles don't have the exhaust issue with carbon that two-cycles do.  Of course, you can clean it anyways, a can of WD-40 and a brush with brass (or stiff nylon) bristles will do a fine job.

If the mower isns't running right, and its a 4-cycle (gas and oil go different places)  we need to diagnose that.
1- Air cleaner element (clean it or replace it)
2- Spark plug (replace it, they're cheap)
3- Fuel filter, if it has one (also cheap, just a little harder to replace)
4- Water in gas tank (flush out the gas tank, the hose going to the carburator, drop the fuel bowl under the carburator if it has one and wash it out)

Try those in order and lemme know what you find ok?