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Any small, single-cylinder carbureted gasoline engine, usually used for lawnmowers. The engine used to create these guides is a Briggs and Stratton 300e series engine.

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spark plug sooty up

i have a tecumseh wood chipper and the spark plug keeps getting sooted up and as hard time to start ? it not a Honda i at to choose that because it had no other to choose from ?

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Typical causes for carbon buildup on the plug would be:

  • Dirty air filter
  • Carburetor running too rich
  • Spark plug running too cold

The fix for the first item is pretty easy; clean or replace the air filter.

If the carburetor is running too rich, you may be able to adjust the mix, or it may be time for a rebuild; small engine carburetors are usually fairly inexpensive and easy to rebuild.

For the third item on the list, it's possible the plug was replaced with one that isn't quite right for your engine, or it could be as simple as replacing it with a new, correct one and/or cleaning and setting the proper plug gap. Getting further into it, it's also possible the plug wire is introducing too much resistance and lowering the current needed for spark, or the magneto could be having problems and not generating enough current, but save messing with that for last after everything else has been checked.

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Thanks Jerry for your input as far as i know the carburetor as no adjusting screws i have cleaned the plug and adjusted it to the correct gap but that made it worse so i closed the gap down to 25thou which made it run better but when i took the plug out to check it it was very shooty again new plug on order now i also running it without the filter just in case it was causing it to choke up do you think that the jets in the carburetor could be the problem ?


Hi brian,

Certainly could be. If you feel confident in your abilities, it would be worth your while to pull the carb and at the least disassemble and clean it out. You can check the condition of the needle jets, gaskets and seals in the process.

There should be a model number somewhere on the engine, and that will let you find the correct rebuild guide for your carburetor. Hopefully the guide will not only show you how to take it apart, but also what to look for as you do.


Hi and thanks to all your answers i decided to go for a new plug and to what that did for the running it did start better only time will tell how sooty it will get i will check it once i've run it for a while and see what it looks like, and if that fails i'll have to strip the carburettor and have a look ?


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brian salmon will be eternally grateful.
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