My Craftsman 16"chainsaw started last week, ran for a while then shutoff and would not start. Mixed brand new fuel, still nothing. I bought a new carb, spark plug and fuel filter, still won't start or even sputter. It has good compression, has spark, tried a small amount of gas in plug hole, even a shot of stating fluid, still nothing. Only thing I can think of is the ign.module although I have spark. I did try resetting the gap, I even pulled the flywheel to make sure shear pin wasn't broken. I am at my wits end, any advise?

 

Usually when you have everything in good working order, the problem is it's flooded.

Compression needs to be above 100 #s and the more the better. The spark should be bright blue across a grounded spark plug gap.

If you have that, try starting it with full throttle and no choke. If it doesn't try to start after a few pulls, dump the gas out of it and with full choke and half throttle pull it over a few times to get the gas out of the carb reservoir.

Then, no choke, full throttle pull it over to clear out all the gas. Then put a teaspoon of gas mix down the plug hole and see if it will fire.

 

Thank you for the suggestions. I tried all of them to no avail, still will not even attempt to turn over. You would think with a thimble of gas in the plug hole it would at least kick. I can see a spark when grounded, whether it's strong enough I don't know. Can only think of the ign.module as being weak.

 

I would try dumping the fuel out of it and removing the spark plug crank it over 20-25 times and let it set overnight with the plug out, refill tomorrow and use normal starting procedures to see if it will start. Have a good one. Geo

 

I think I can rule out fuel and flooding. Took everyone's advise, drained system, blew out cylinder with compressed air also pulled over about 30 times. I let sit overnight tried a spoon of new fuel...nothing. I want to thank you all for your advise and if you can think of anything else please do. Maxwell

 

How did you determine you have good compression? If it's low that's likely the problem.
If you don't have a compression gauge available, pull off the muffler and look for scoring on the piston and inside the cylinder. If you have some the compression is likely low.

You can also get damage from heat when running a chainsaw in hot weather for an extended period. I typically use more oil in the gas mix in hot weather.

 

So I borrowed a compression tester with the rubber end, had 80psi. I did take the muffler off, could not see much in the way of wear or scoring. I would think I would get a little something in the way of starting with 80psi. ??? not sure how accurate those old testers are, it is old. Maxwell

 

The 80 lbs is low end border line. Try putting a spoon of motor oil down the spark plug hole and tilt the saw a few directions to spread the oil across the piston. Then retake the compression. If it jumps up to 120+ lbs, it would be a good saw to put a piston ring in, given the cylinder/piston isn't scored. If you go that route, put new crank seals in it too.

 

It should run some with 80 psi. It might not idle well but it should fire up and run full throttle. If it's a dry cylinder, 80 psi might be normal.

Might check the flywheel key.

 

I have a craftsman weed wacker so I decided to compare compression, sure enough jumped to125psi on the first pull. I disassembled the chainsaw engine and found enough damage to piston and the ring to be the cause, cylinder is not to bad I think I can use some emery cloth to smooth. Going to get a piston and ring kit and give it a try. Just have to figure out how to reinstall the piston in the cylinder without a ring compressor. Thanks again to everyone with your help. Maxwell

 

Just get a large hose clamp.

 

Wahoo, chainsaw has come back to life. Thanks again everyone.