Craftsman Chainsaw Issue.

Jay87T

Member
Hey guys my brother got fed up with this Craftsman chain saw and tossed it in the trash, I took it out and decieded to fix it, its in very good condition. I dont know the model number because the sticker peeled off, problem Im having is. it starts when its cold. and runs then dies after a bit. just shuts off. Its hard to start again, and if it does i cant get it to idle. I changed the Zama Carb with a new one, I changed the fuel lines, filter in the tank, gas cap and the spark plug. I see there is plenty of fuel in the priming bulb. I adusted the H and L 1.5 turn from being seated. I still cant get it to idle even with the idle screw turned all the way in, Im thinking now maybe it could be electrical? any Ideas what I can look for?
Thanks.
 
Which idle screw, mixture or speed? Mixture should be screwed out 1 1/2 turns and same for high speed for initial settings.
 
yep have the H and L turned out 1 1/2 turn and the idle screw fully screwed in. I cant get it to stay running.
 
It'll also do that if you have a bad gasket or seal in the crankcase because it'll suck air through that hole rather than the carburetor. My weed wacker was doing that this last summer, it was a bad gasket under the reed plate housing.
 
I would bet that you have a crankcase leak. Most likely the crank shaft seals. They will seal when cold but leak when hot. You need to do a crankcase pressure test.

To do this you need to plug the intake where the carburetor mounts and then the exhaust port where the muffler mounts. I usually see a small piece of thin flat rubber. You can clamp it over the holes with a small metal plate. Also plumbing rubber plugs work too.

Then I have made pressure fittings out of old spark plugs with the porcelain knocked out and a fitting brazed in them.

Now you can use air pressure or vacuum. Usually 3-5 PSI is all you need. Never go much over 5 PSI or you will hurt the motor.

Pressurize your cylinder block. It should hold pressure/vacuum for at least 4-5 minutes before leaking off. I use pressure and then spray soapy water around the crankshaft seals and all joints in the crankcase.

I would bet that it is the crankshaft seals leaking. That is a very common issue. Your carburetor need the pulse from the piston moving in and out to make it pump fuel. With a crankcase leak this pulse is smaller or not there at all. So the carburetor can't pump fuel.

Figure out what is wrong than buy parts!!!!
 
Just curious - what size saw and vintage? I ask because I had a few 55 cc Sears beaters that were made by Poulan. They were pretty good for el-cheapo saws. But I then made the mistake of buying the "Incredipull" 55 cc "Sears Best" saw to leave at a camp. Made in Malyasia and parts were discontinued for it a year later. What a piece of junk. I give it an award for being one of the worst chain saws ever sold -at least recently. Same saw was also sold under the Cub Cadet name.
 
Your brother did a smart thing. Not trying to be a b-head but I had a poulan that caused all sorts of problems. It would start but had to readjust the carb every use. Poulan made saws for craftsman for a while maybe they still do.
 
thanks for this info, this sounds like it could be my issue. I think that the fuel is cutting off being pumped into the carb. this would explain why it so hard to start again when its hot. now Im sure its a poullan chainsaw. Withought the crafsman sticker on it, wonder how I can get parts for it.
 
I had a similar issue with one. I fixed mine by throwing it on the shelf to rot. I knew it was a cheap trim saw when I bought it but needed something in an emergency. I have another Craftsman here that is pre-compliance and has a metal case. It sits for a couple of years and starts and runs perfect in five pulls. They just aren't made that way anymore. I'll stick with my Dolmar for everyday use.
 
many of the Poulan based saws use a carb intake boot between the carb and head. They are notorious for developing cracks and leaks. Symptoms are exactly what you describe.
 
Hello jay87t,

Take the plug wire out, grab the plug and see if you can shake it back and forth. Bet you got a loose head/cylinder bolt/s. Just tighten and go cut some wood! If it is electronic coil/ignition, when they go bad at times quit when hot only.........

Guido.
 
Have you checked exhaust port for fouling? Carbon buildup at top of exhaust port in effect 'chokes' inflow because outflow is restricted. Decoking of 2 stroke engine a normal maintenance procedure for premix fuels yet. Fouled muffler/spark arrestors another exhaust restricting issue that effects intake air. Fouled exhaust would give you about 1/2 your symptoms- it is a quick thing to check. RN
 
What I do first with those saws is check the compression. Put a compression gauge in and pull until it stops going up. (at least 8 pulls). If it doesn't go at least 130 psi. the compression is too low. If you can get it to 130 psi cold, run it until it cuts off. Then check it again while its warm.

I Bet it will be 120 psi or below and that is about too low to run and if it does start it won't idle.
 
You're going to spend more time and money in parts on this saw than it sold for new, to "fix" it only to have the problem reoccur in a short period of time.

There's "waste not want not" but also "penny wise pound foolish."
 
Had a similar problem with my Dad's old Poulan. It's been awhile, but if I remember right it turned out to be the fuel pump tube that runs from the carburetor down to the crankcase.
It was an easy fix once it was apart, but I had to pretty much disassemble the whole saw to get to it.
Pete
 
What you described and how you said it, it sounds like a bad coil to me. As the coil warms up it gets further and further out of specks to where it will not run until it cools off again. This happens as the coil starts to break down. Cracks get bigger and leaks voltage soon the coil will completely break down and may leak oils. USE GLOVES when touching old oily coils
Good luck
Fat
PS It just hit me .. Check your carb for water in the inlet valve or in the vacuum pump diaphragms if so change fuel. Those carbs are so small it only takes a drop.
 

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