Some chain saw advice please

[Mike Field]

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I have a small Stihl chain saw that's playing up. I use it only occasionally (for sawing up firewood,) and when I got it out the other day to tackle a fallen black wattle I found that though it would start and run okay the moment the load came on it would stall. I doubt you could cut a cheese with it the way it is.

On reflection, I think it displayed some of these symptoms last time i used it, although on that occasion I was able to get the job finished.

I'm quite happy to take it to the agent to have it repaired, but I'd value some informed opinions from you good people first -- I don't want to find myself stuck with an $80 bill for adjusting a choke needle or something.

Any ideas from the experets out there please?
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[Del Lansing]

My routine when I hit similar symptoms is to replace the sparkplug, dump out the gasoline that is in the tank. MIX NEW FUEL PRECISELY. Add Stabil(r) additive to the new mix. Get it running good and hot under no load and try cutting again. Old gas will leave a 'varnish' in the tiny passages in the carbureter and leave the unit starving, hopefully the new gas and Stabil(r) will dissolve the goop; depending on how much is built up. If that doesn't work and you don't feel up to tearing apart the carb I guess it means a trip to the mechanic.

[ 04-04-2005, 10:33 PM: Message edited by: Del Lansing ]

[Stiletto]

Check the air filter, After that if it is idling ok turn the high speed screw in a little and try, and then out a little and try. (remembering where it was when you started) If you are up to stripping the carb you may find some sawdust inside which got past the fuel filter, while you have the carb apart put the diaphragm over the end of a torch(flashlight) and make sure there are no pinholes in it.

[Thad]

ditto Stiletto, clean the air filter then try again.

[Ron Williamson]

If you turn the high speed in too much,you will own a new anchor.
Be careful
R

[cs]

I say ditto again on the air filter.

Chad

[Mrleft8]

Pretty much what everyone else has said, but add: Stihl's are notoriouslt rattly machines, and the adjusting screws tend to work themselves out of whack. Close the high and low adjusting screws completely, and then open them back up the proper amount (there should be a little diagram stamped into the shroud right next to the screw adjusting holes). Clean the airfilter AWAY from the saw, or you'll just end up blowing trapped dust into the parts that the filter is supposed to protect. And one other thing to check is to see that the chain isn't bound up. A stuck chain can stall out an un-warmed up saw.

[Alan D. Hyde]

Is the chain brake (anti-kickback brake) malfunctioning?

Is adequate oil getting to the cutter bar?

Is the exhaust port/muffler clear?

Alan

[Mike Field]

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Thanks guys. I'll let you know how it works out.
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[Bob Smalser]

After cleaning the air filter, the first thing I check is the fuel filter at the end of the pickup tube in the fuel tank on saws that have them.

[Dave Hadfield]

Take the carburetor off and clean it, then re-assemble and set the mixture exactly as per the manual. And clean the plug with acetone, and gap it.

Above all, use filtered clean fresh gas with good 2-cycle oil and ALWAYS put in fuel stabilizer.

Last Fall, bad gas cost me $500. The fuel in the tank of my Husquevarna was 3 months old. The 'snot' that congealed out of it part-plugged the orifices in the carburetor and ran it too lean, so that under full load the cylinder temp got too hot, and cooked it. HAD TO BUY A NEW SAW!

[michaelc]

As noted above, you pretty much have a mucked up carbuereter which will need cleaning. If the old gas shellac-ing isn't too bad, try some carbuereter cleaner spray and use a higher octane gas (premium -as the $$$ rattle by), and as said already, use a stabilizer mix with your gas especially if you aren't running it regularly (eg.3-4x/week). Small engine mechanics tell me that there are lots of brands of stabilizers out there that are just junk. Two Stihl service shops near me claim the widely used/sold Stabil is just so so and they recommend a stabilizing solution marketed by Briggs & Stratton. I can't vouch for the quality of any of these agents, but after spending a fortune in time and money getting small engine tools working properly, I've taken to using their advice. I also try to start most machines regularly, even in the dead of winter. There is also a controversy about how to store machines between infrequent uses: Some claim (many manufacturers) that all gas-oil be drained and/or consumed before storage, while others believe tanks should be topped off with gas-oil/stabilizing agent to exclude air. i have yet to figure out which is best, seems like everyone just touts their own practice. Hope something here helps.

[sailordwc]

Quite often 2 cycle engines lose power under load simply because the screen in the exhaust port or muffler is gooped up. Check that first, along with the air filter. If you still have the problem after checking/correcting those, I'd try replacing the fuel mixture as someone recommended. If it persists, then I expect you've got a gummed up or maladjusted carb.
good luck!

[Ken Hutchins]

High test gas, good quality oil, clean air filter and muffler screen. Now that the carb has been mucked with, set it properly then forget the adjustments exist. I've been running a Stihl 032 for over 25 years and have NOT EVER touched the carb adjusting screws. Perhaps the diaphram and/or fuel inlet needle needs replacing (I've changed them 4 or 5 times) Another thing to check is the vent in the cas cap, it is a hole with a cotter pin in it the cotter wears a groove around it from vibration and plugs the hole creating a vacuum in the fuel tank, replace the cotter.