I should add it's been suggested that maybe me mix is not proper based on another post I made in the tractors forum that I kind of forgot about. I'm running it 40:1 now as specified, using MTD 40:1 oil. I honestly ruled it out as my Craftsman Laaf Blower and chain saw bought within a year of this trimmer all run fine on the same fuel, but is it possible?

Try running it with the choke 2/3 of the way on, if it runs better the mixture is to lean. If the unit is old it could be leaking crankcase seals and probably not worth fixing. Most likly a carb adjustment of the mixture screws will do it though, possibly a carb rebuild (cleaning and new diaphrams). How old is the trimmer?

k first of all how old is the trimmer?? i own a craftsman 25cc line trimmer, personaly i don't think there is anything wrong with your mix, the manufacture says to use 40:1 in them, i run 32:1 in mine and have had it for 2 years, still starts good runs good, if your mix was bad there would be oil build up in the exhasut and it would smoke excessivly. if it was too lean it would burn your motor up what i mean is you would of burnt the seals, wich i think you might of done. does your trimmer have low compression? if so its probably due to a seal leak, this would cause it to die when idleing adn will casue it to die when you jump on the throttle. personally the only way to fix it would be to completley tear it apart, then either buy the new seal kit, or go get some automotive reseal and apply it to the seals yourself, also use thread locker on the bolts and screws when putting it back together get the medium strength stuff so if you need to you can take it apart again. i had to do this to a weedeater bc 2500le cause the seals went bad and it would vibrate itself to peices, now it works like new and i've had it for 7 years and worked it to hell and back.

I apologize for the slow response, I don't have a lot of time to check this. The trimmer is going on 4 years old. I can check compression on it... the unit does not smoke a lot either. If the seals are bad though, wouldn't it have already died? This started pretty much from the start of last year, and hasn't improved but hasn't gotten worse. I will try the choke though and see what happens to it; worth a shot as it sounds like either way I'll eventually need to buy a new trimmer.

Also, I don't know if it matters, but I would occasionally see some kind of condensation on one or two of the fins by the exhaust. I never put much thought it into it and just figured it was due to the extremely hot and humid climate of the shed. It wasn't fuel as far as I could tell/smell.

really need to know what model of craftman. the 31CC are different from the 25CC. and the 4 strokes are also different. I don't like the 31CC with the spark plug on the bottom. I had one and one day needle bearing came out the exhaust. I wondered why it vibrated so much???!!?? I didn't like the way it ran before it too a dump away.

It is the 32CC 2-cycle, spark plug on the bottom type. Got it out yesterday and did some work with it... adjusting the choke made no difference, ran the same as it has, though I think part of the reason is when I would give it some throttle the adjustment lever for the choke would just fall back down to open.

Look at the muffler and try to locate the "spark arrestor" (it's a little screen) if you find it and it is partially plugged thats the culprit.....heat it up with a propane torch and burn/blow off the carbon build up,reinstall it ,and give that a whirl .....if the spark arrestor is plugged the little engine can't exhaust (it can't breath) ....all 2 cycles come thru with a spark arrestor ....you can thank your government,they don't like it when you set the woods on fire,from hot carbon ehausting to dry grass/brush....Jim