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1 Posts
Discussion Starter · #1 ·
I have a McCulloch Eager Beaver model 60012312 chainsaw. I purchased the saw used on craigslist from the seller who said it "ran good". Got it home and after 10-15 minutes of use it would shut off. Someone told me to clean the carb, which I did.

The carb inside was mostly clean, except for a small amount of varnish. Now the carb is spotless clean inside. The mesh screen filter was cleaned as well. The two diaphragms inside the carb were flexible and not brittle or dry-rotted. I also replaced the fuel line, which was dry-rotted and cracking, as well as the air filter.

When I reassembled the carb and put the saw back together, it would not start. I tried turing the hi and lo mix screws all the way in and then back out one and a half turns. I tried turning them all the way in and then try starting it there. Sometimes it would cough and it did start briefly once or twice but then quickly shut off. I also tried using starting fluid and it started but again quickly stalled out.

I took out the spark plug. It had carbon build up and fuel residue on it which I cleaned and lightly sanded.

What else should I try to get this thing started and running normally?

14 Posts
Things I check which you may/may not have already done:

  • Remove plug & check plug gap.
  • Insert 1/4" x 1 1/2"-2" long screw into plug boot, hold screw head ~ 1/4" from chassis, pull start cord & check to see if spark jumps from plug to chassis. If not, or if very week - change plug.
  • Install plug, pull start cord. If doesn't start, remove plug to see if fuel is getting to spark plug/cylinder. If not - fuel is blocked.
  • Check fuel filter - clean or replace if required.
  • Check air filter - clean or replace if required.
  • Apply carburetor/choke cleaner to all accessible carburetor surfaces, ports,
  • Clean HI/LO jets.
  • Blow out all carburetor ports, fuel lines, etc with compressed air (30psi)
  • Adjust idle speed screw & HI/LO speed jets.
  • Reassemble all filters & fuel lines.
  • Attempt to start. If fails to start, remove plug, check if fuel getting to plug. If not add1 tspn fuel to cylinder & wet plug.
  • Restart, if starts & then doesn't continue to run. Remove plug to see if all fuel burned off & no more fuel is getting to plug.
  • Problem is most likely with carburetor.
  • Totally disassemble carburetor & place all removable parts in container of carburetor/choke cleaner for a few hours, even overnight. Check for dirt.
  • Blow out all orifices & lines with compressed air (30 psi).
  • If an old chain saw, the problem could be ethanol fuel eating away fuel line/screen/diaphragm components.
  • What I believe is happening is that the ethanol has dissolved the rubber in the fuel components (i.e. diaphragm) which will then prevent the down stroke of the piston from creating a vacuum & pulling the diaphragm which will then not draw the fuel from the tank into the carburetor.
  • Rebuild carburetor with a carburetor rebuild kit using OEM or OEM equivalent components: diaphragm, screens, needle valve, etc. Basic kit does not include carburetor which would be ~ $50, it includes only the components just noted & costs ~$15.
  • I just had a frustrating experience trying to get my chain saw to start & I concluded the ethanol was the root cause of the problem. Once the carburetor was rebuilt, it started & ran like new. Check out my thread in the "Equipment Repairs and Maintenance Forum".
  • Good luck with your saw! Hope I didn't forget something>

24 Posts
I had a stihl fs 66 trimmer that sounds similar to your problem . I covered every base several times, even rebuilt/cleaned the carb twice. My fix ended up being a used different carb. It may be nothing more than a Walbro gone bad........ good luck
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