I having trouble diagnosising the problem with my lawntractor. It misses and won't start after running a while. I have replaced the air, fuel filters and changed to new plugs. I have replaced the magneto and still no results.
Any advice?

 

sounds to me like you might have 2 problems the engine is overheating
so make sure engine is kept clean especially around cylinder were the fins are located. and you might need to totally clean carbuerator if it has electric choke it might be bad or gummed up

install or replace fuel filter and keep engine and carb clean a clean engine runs cooler and last longer hope this helps

 

Are you getting spark after it won't start? If not then the coil is your likely culprit.

 

Any ideas what engine you have? (brand, hp, model#)