Stationary Engine List

Fouled Spark Plugs and Sealing Gas Tanks


| December/January 2001



Stationary Engine

Two topics for the price of one this month! What to do with fouled spark plugs and how to clean and reseal gas tanks are two subjects that come up quite regularly on the Stationary Engine Mailing List. Both are problems most engine collectors will have some experience with at some time or another, so some of this information should come in handy. The original query came from one of the young collectors on our list, and the responses were from collectors around the world, young and old! As ever, the following comments reflect a variety of opinions that surfaced during this discussion.

Fouled Spark Plugs

One of my -inch spark plugs is fouled. It won't fire, but I can see it sparking inside the bottom. Can I clean it? These plugs have lasted a year, until I ran them in the Witte. I soaked them in some gas, and got one to fire again .... gonna soak them all night one day and clean them out real well.

Someone told me to soak it in ammonia -said it takes the carbon out. All it did for me was eat at the aluminum screw terminal. Someone also told me to use starting fluid - never did though. I use a needle to dig down inside and scrape it out.

I have been using a long reach Maytag plug in my 3 HP headless Witte and have not had a problem with fouling.

If you are using a 3095 in that 5 HP Witte, THROW IT AWAY and get a take-apart plug. I NEVER could get a 3095 to run my 8 HP Witte for more than two hours. Then had to buy a new one. The take-apart (I paid $20) saved me LOTS of bucks over the years!

Your fouling is probably caused by carbon buildup on the insulator. Carbon is a conductor, so now the electricity has a path that is lower resistance than the air gap between the electrodes. Douche it out with brake cleaner, ether or some other kind of solvent, then with a stiff piece of spring wire (such as comes off a street sweeper), poke a thin rag down there and wipe it off. Take your time and do it well.