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Thread: Chain saw won't stay running, etc.

  1. #1

    Question Chain saw won't stay running, etc.


    I have a Homelite 20" chainsaw that is about 6 years old. It will start, but when it does smoke comes out of the exhaust for about 30 seconds or more before clearing off. Once running it will run continuously just fine as long as you have your finger on the throttle. Take your finger off the throttle and it stops immediately. So, it won't idle. Then if you want to start it again, it won't start unless you have your finger on the throttle while pulling the cord, and I know that you should be able to start it without doing that. I've used the saw for well over a half hour, cutting wood, and doing my work, but I was just real careful to not take my finger off the throttle.

    Can anyone give me some idea as to what I can do to fix or service my saw?

  2. #2
    Join Date
    Dec 2003
    LaLa Land, NW Ohio


    First, make sure you have fresh fuel and the correct mixture.

    It sounds like the carb needs cleaned out or rebuilt. Ethanol in gas attacks rubber parts in carb's. They are usually not hard to rebuild. Check youtube, I have seen some very good step by step instructions on there.

    If it has adjustment screws and/or ports you can remove them spray a shot of carb cleaner into the hole and clean out the ports (they are very small and you sometimes can not see them). Reinstall everything and set the screws to their initial/default startup settings and tune them out.

    Most newer engines have a 1 piece plastic carb or no screws and there is little that can be done other then replace it.

    If you see any small pieces of rubber fall out of any of the openings, it's rebuild time. (ethanol got it)

  3. Default

    Get a can of SeaFoam at your local Wally's World, NAPA, or ??

    As Mr T. says using fresh gas and the correct mixture of the correct 2-cycle oil (for air-cooled engines -- I personally use AmsOil Sabre 100:1), make up some new saw gas. Give this Gas/Oil mixture a health dose (twice the rate recommneded on the can won't hurt) of the SeaFoam and use your saw. You may notice it smoking a bit more than usual after a bit as the SeaFoam cleans the deposits from the tank, lines, carb, piston and such.

    I do this and then run the same "saw gas" in all of the 2 cycle tools (3 chainsaws, leaf blower, string trimmer, mini-tiller, ....) It doesn't matter if the unit calls for 32:1 or 50:1 or 20:1 they all get the 100:1 mixture with synthetic 2-cycle oil and Seafoam mixed in. I have run the Gas/Oil for many, many years and have been using the SeaFoam for the last 6-8 years and I haven't had ethanol problems in a single 2 stroke unit.

  4. #4


    I was going to do what Mr. T suggested, but now I think I'll try the Seafoam idea first. So, if I can't find that Amsoil 100:1 around my area, I'll mix up some new gas with the recommend ratio, and then add 1 or 2X the recommended amount of Seafoam and use the saw as I normally would - cutting logs. So, if that doesn't do the trick, the ethanol has probably damaged some of the rubber seals and/or the carb, and that would mean the carb needs to be rebuilt. Yes?

  5. #5


    OK, I found an AMSOIL dealer at a truck stop all the way on the other side of town, and bought the AMSOIL Saber Professional 100:1. I also bought some Sea Foam. I went and bought some fresh premium ethanol-free gasoline. I then mixed in the recommended amount of the AMSOIL (1.3 ounce) per 1 gal. gasoline, then I mixed in 1.5 ounces of the Sea Foam. I filled up the tank, and tried to start it. It started just fine. It did smoke (white) for about 5-10 second, and then that stopped. It had been smoking before upon starting (as noted on my original question) so I'm not sure if this was the GOOD smoke (Sea Foam induced) or BAD smoke (the same smoke I had before). Any way I continued to run it for a few minutes, and let if go down to idle, and indeed it did idle (so that's a good thing). I then put it to work cutting a large log, and that was fine, but when I was done doing that and took my finger of the throttle, it immediately shut down, just as happened before (which was my original problem all over again.

    Before I go to the next step to rebuild the carberator, I watched this video on YouTube which was made by the Sea Foam company itself, and it says to put 1/2 to 1 ounce of Sea Foam directly into the gas tank with the gas (higher ratio than my 1.5 ounce per gallon of fuel) and also pour the same amount directly into the carburetor once it's started. Here's the video, and I want to know if I should try that before I try to rebuild the carburetor??


    (By the way, I did run some of my other 2 cycle tools (blower and a Mantis Tiller with the AMSOIL and the Sea Foam mixed in, and they both ran very nicely after a few minutes of running those engines)

  6. Default

    I would most definitely go with a higher concentration of the SeaFoam. Its solvents and detergents will soften and dissolve deposits in the tank, lines, and carb. Run the saw so that it gets thru and then let the saw sit over night (time for it to dissolve/clean) and then run it pretty hard (do some work with it). The Seafoam is not an instant fix, but as you run several tanks thru it should clean it up.

    I am assuming that you keep your air filter clean so that it is not causing it to run rich (clogged air filter is like trying to run with the choke on).

    Maybe the saw just needs a bit of a tune as well (adjusting the low and high speed mixtures and idle speed).

  7. #7


    OK, I did the whole fresh gas, AMSOIL Saber 100:1, Sea Foam thing + plus I washed the air filter in soapy water and dried it with my daughter's hair dryer (don't tell her). And I can happily report that it is running tremendously better. It's rarely stalling, and if it does I can start it right up again with no problems (no starting it with the finger on the throttle any more). The idle speed is still a bit unpredictable though: sometimes it idles with the chain stopped and just jumping forward a bit, and sometimes the chain is just constantly going around. Doesn't seem to be a real big deal though. Turning the idle adjust screw counter clockwise didn't seem to help. Oh well, maybe running a few more cycles of fresh gas with the AMSOIL and Sea Foam will work that out.

    Thanks for the suggestions!

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