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Service & Maintenance Question

    Bill H
    Husqvarna 356BT. When it gets hot it stops running. Replaced...escalated
    Service & Maintenance Question posted November 23, 2013 by Bill H 
    1839 Views, 4 Comments
    Question:
    Husqvarna 356BT. When it gets hot it stops running. Replaced the fuel, ignition and carburetor. The new carb- started second pull and ran great for about 1/2 hour, then died like it ran out of fuel. Whats next?

    Answer

     

    • Karla

      Bill

      I received your E-mail, I will try to answer your question but I normally work on chainsaws.

      Anyhow, I am not exactly sure by your description of replaced the fuel, ignition, and carburator which parts you have checked or replaced. (ie. new spark plug? New or cleaned air filter ? New fuel filter in fuel tank ? etc.)

      I see that you stated that you installed a new carb. Does the 356BT blower have a carburator primer bulb, and did that get replaced with the carburator or is it seperate from the carburator ? If its seperate, did you check that the primer bulb check valve is working properly? Is the primer bulb holding fuel or does it drain right out after priming or after it shuts down? If it drains out then I would suspect the primer bulb, and replace it.

      You stated your engine is getting hot, I am assuming you are using the correct oil to gas fuel mixture. If the engine is getting really hot, then this is obviously not good, and I would probably suspect some kind of internal engine problem, but before taking the engine apart, I would remove the muffler, and check the spark arrestor screen on the muffler and make sure it  is clean of all carbon. Sometimes the screen gets plugged with carbon, this will make the engine run hot, and also stop the engine from running at full throttle.

      While your muffler is removed, I would manually turn the engine over by hand, and look inside the exhaust port, and see if you can see the condition of the piston, piston rings, and cylinder walls. You are looking for any scratches, scuffing, or grooves of damage intenal to the engine. If the engine looks good, and the exhaust screen is clean, (note: you can clean the spark arrestor with a small brass or wire brush, or you can heat the spark arrestor with a small propane plumbers torch until the carbon comes off). Then put everything back together.

      If you see scoring on the piston, then you will need to dissassemble the engine to do a further and more thorough inspection, and if the rings are scored, then replace the piston rings.

      If you have access to an air compressor, since you stated the engine is getting hot, after everything is back together, I would make sure I used some compressed air to clean the fins on the outside of the cylinder, and that there is not alot of debris blocking any of the air ways around the outside of the engine.

      I hope this helps.

       

      • Bill H

        Karla,

        I dumped the old fuel and filled the tank with fresh Premixed two cycle fuel- no ethanol, 93 octane, with two cycle oil mixed (sold in quart containers). New spark plug, new ignition module, new carburetor, clean air filter. Its not getting that hot, but I will blow out the fins. The spark arrestor screen is clean. Combustion chamber looks pretty good, no excessive carbon. Seems to have good compression. This engine has a primer bulb for the fuel line to the carburetor. It hold fuel and does not drain right out. I noticed that after sitting a couple days, the fuel line to the top of the carburetor made noise- after I removed it from the carb. Like a small vacuum. I could put my finger over the open end of the fuel line and stop the light noise. I wonder if the fuel tank cap needs to be vented? I think I will try pumping fuel thru the carb with the primer bulb next. Thanks for your help.   Bill

        • Bill H

          Karla,

          Would you believe the problem was the ignition module. I pumped fuel thru the carb and back to the tank. Looked ok here. I thought- well check the ignition with the spark tester I just purchased.  Well, no sparks. (I baught a new ignition module and couldn't see any sparks, so I baught a second ignition module before I realized I needed a spark tester to see the sparks.) The second ignition module was defective and failed when it got hot. So I put the first new one back on and lots of sparks.

          It now starts on the first pull. Bless the little spark tester or I would still be working on it. Ha  Runs like a new one! You provided excellent, very detailed advice. Thank you. 

          Bill

    • Karla

      Bill.

      Thank you for the compliment, and your repair updates.

      Glad it all worked out, and you have it running again.