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JohnF2015, Small Engine Technician
Category: Small Engine
Satisfied Customers: 993
Experience:  Owner/Service Technician at S & J Small Engines
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Husqvarna 240 chainsaw - installed new plug, used up one

Customer Question

Husqvarna 240 chainsaw - installed new plug, used up one tank of fuel, could not restart saw. Plug deposits are white which I think means it is running hot. Not brush cutting but tree cutting. Run saw hard on entire tank of fuel. Any thoughts? (Maybe add a little oil to gas mix or adjust high speed needle to richer setting.)
Submitted: 2 months ago.
Category: Small Engine
Expert:  JohnF2015 replied 2 months ago.

Hi, my name is***** will be assisting you.

You are correct in that the deposits on the plug indicate that the saw is running hot. I would suggest adding a little more oil to your fuel mixture to take care of that. However the damage may have already been done since you say you can't get the saw restarted. It may have damaged the piston and cylinder from a lean fuel mixture and getting so hot. What kind of compression do you now have on the machine?

Customer: replied 2 months ago.
It does have compression and does not appear to have changed in psi.
Expert:  JohnF2015 replied 2 months ago.

You need at least 90 psi in order for it to start and run properly. Sometimes you can get them to start if at 85 psi but it is really hard you may have to pull it 15 times really fast to get it to fire up.

As long as the compression is still good then you should be fine to add a little more oil to the mixture. Instead of running it at the recommended 50:1 I would run a 40:1 mixture which is 3.2 ounces of oil per gallon of fuel.

Thank you it has been a pleasure to assist you.

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