Homelite 240 Problems...need advice

[rocky_mtn]

Hey guys. Long time reader, first time poster. A guy at work asked me to take a look at his chainsaw (Homelite 240 UT-10630-B) to see if I could determine why it won't start. Got it all taken apart and cleaned the carb thoroughly and everything checks out. Gaskets and diaphragms all look good and are nice and pliable. I've taken the fuel tank and oil tank out and checked the duckbill vents, the filters on the oil and fuel line, the reed assembly and the muffler to see if it was clogged (didn't appear to be). I've got a few things I was hoping someone could help me with. First things first, it does have spark and will run if fuel is introduced directly into the intake or spark plug but that is very short lived...maybe 5 seconds. If I pour a little bit of gas on a rag and set it over the intake with the air cleaner removed, it will run for quite some time actually. I've had it running like this for up to 1 minute. If I feather the throttle it reacts as it should, and if it starts to die out, pulling it to wide open throttle seems to correct it and it keeps running. It will eventually just quit running though. Aside from the hard starting and keeping it running problems, I've had it apart 3 times and have "lucked out" with regards to getting the lockout lever spring and throttle lever put back together correctly, with the exception of this last time...I can't seem to get the darn spring to work correctly and seat. As far as I know I have it placed correctly around the throttle lever, but I can't seem to get it to seat on the lockout lever. I'm not even sure where it's supposed to sit. When I had it together the previous two times, everything worked flawlessly with regards to the lever and throttle. Push lockout lever, engage throttle, disengage throttle, lockout lever springs back to locked. Now I just can't get it, it just seems to be binding and I don't want to goof the spring up. I'm guessing new parts for this machine are likely scarce. Any advice? I have taken photos of the lockout lever assembly and uploaded them to my photobucket, so let me know if anyone thinks those would help. I need to get the throttle working right so I can move on with why it wont run and start. Any help is greatly appreciated. Thanks in advance. One side note I almost forgot...I thought maybe the crankcase wasn't drawing enough vacuum to draw fuel to the carb, but I don't think that's the case. After having it running for a minute or so, I started to tear it back apart and starting to hear a hissing sound. It was coming from the fuel cap. After I removed the fuel cap, the pressure built up released and the gas appeared to boil. Maybe it was just air or bubbles, but it did it for a solid 20-30 seconds and as air bubbles rose, the fuel level in the tank dropped. Not sure if this is of any value, just thought I'd add it. I don't think the saw was warm enough to boil the fuel by any means. This is when I checked the duckbill style vent in the fuel and oil tank. They seem just fine.

 

[a. palmer jr.]

You can try replacing the cap. I think those vent from the cap. A test would be to loosen the cap when you run it and see if it helps.

 

[rocky_mtn]

Thanks for the reply palmer. Figured I'd follow up for posterity in case anyone cared...Finally got the dang lockout lever spring in place after fiddling with it for hours. As for the running problems, it was only registering about 80-90 psi on the compression gauge. Took the muffler back off and re-inspected the rings and they appeared locked on the piston. Raised the piston just above the exhaust port so it would hold fluid, and poured a few teaspoons of sea foam down the spark plug hole and let it sit for a couple days. Wouldn't you know, now I'm back up to 130 psi on the gauge. Threw the muffler back on along with the bar and chain, set the tension, set the low and high speed screw on the carb...fired right up! After a few quick adjustments, its running like a champ again.

 

[a. palmer jr.]

That Sea Foam must have unstuck the rings. I'll have to try that..