Chainsaw dies when hot

M2theB
New carb kinda makes me think it may not be that screen. If the fuel line/filter and carb were all replaced at the same time, and delivery is still and issue, tank vent and line/filer flow capacity would be questioned.

 

im with you.
Except that pic of the wet muddy one is post carb clean, new filter and new line. Just didn’t rinse the old tank. Why or how it collected on that filter, i can’t answer.
I’d think it not likely too. And it’s really easy to check.

 

Have you checked your gas???

The following all happened over the coarse of a week:

I was convinced my 261 m-tronic had a plugged up tank vent or a bad solenoid. It would run to 1/2 tank then start stuttering then die, restart & idle fine but couldn’t give it any throttle. I reset the m-tronic, no change.

Then my 661 non -mtronic started doing the same thing,1/2 tank then start stuttering & die
One saw fine, two saws doing the same thing unlikely but possible...

Then my 462 non m-tronic same thing, no freaking way all three had plugged up tank vents or solenoids crapping the bed at the same time.

So I parked them to go over them to check everything out. Pulled the carbs, they were clean, dumped the gas looking for debris & checking filters. Everything looked good, tank vents were not plugged. Air filters we’re good also.

I grabbed my 440/460, same damm thing, 1/2 tank, stutter, die, restart & idle fine, give it throttle- blah. I was pulling my hair out, they all started great, ran great till 1/2 tank then blah.

New saws, older saw, m-tronic & non m-tronic all the same thing.

I mixed up a new batch of gas, put it in the 440/460 & it hasn’t missed a beat since, new fuel in the other 3 & same results - haven’t missed a beat.

I am still bam-boozled by the situation, why 1/2 tank was the magic spot,bad fuel didn’t even occur to me because they started & ran fine till 1/2 tank, why the m-tronic & non m- tronic did the same thing at the same fuel level. The fuel didn’t smell nasty, I put some in a quart jar to check for separation/water but it still looks like it did the day I dumped it in.

Long story - short. Check your gas.

 

I replaced the new fuel line with another new fuel line that the ID looks bigger and had the same issue. Next I replaced the new black fuel filter with a new white fuel filter, same problem. Next I replaced the primer lines with new and same issue. Next the primer bulb cracked so I replaced that with a new bulb and same issue. Now basically everything is new

 

Clean the air filter? Have you checked it or not? Just curious....

 

I mixed new gas and had the same issue, changed the gas cap with the vent in it and same issue and the air filter is clean. I will try and post a video

 

OK.

The reason I've asked twice is because my saw was doing the same thing years ago and all it needed was for the air filter to be cleaned. Carb cleaner and air hose....

 

When I was having my saw troubles, I talked to a fella that recommended changing the air filter, said he had a saw acting up, the air filter looked good but he swapped it out & voila it was a perfect runner again.

 

I will try that next I guess. I have new air filters from the carb kit I bought a few days ago.

 

So all that’s left to change is the air filter & coil ?

 

Coil was my next area of attention.



Edit: well, after watching the vid, I’d be looking at new saws.. must be super frustrating. Have you a screwdriver and move the H screw about 1/4 turn, try it again. Keep making 1/4 turn increments and see if it helps. That doesn’t really seem like a coil issue, unless it’s putting out a very weak spark.

 

I have burned through 1 and 1/2 tanks of gas trying to adjust this saw. I have the spline tool and adjusted the carb. Initial setting was 1 and 1/4 turns out on both H and L. Then kept moving the L out until it sputtered and almost stalled. Then backed the L screw in 1/2 turn. Next gave it gas and it would stall so started turning the H screw out - 1/4 turns only then hit the gas. Finally I would be able to idle and hit the gas and get OK response but not great response. Then after all the messing around it was flooded and I would let it sit for 30 minutes an hour. When I go back the result was in the video. It starts and I can pull the trigger and it runs high for a minute or 2 then as it heats up the stalling happens on full throttle.

 

That acts like the fuel tank vent is not working...I had one (PP4218A) that acted exactly like that with running less and less each time...I can't remember if I swapped out the cap with an old parts saw, or if I fixed it...I wanna say I fixed it...I think maybe I blew through the vent hole (tiny hole dead center on the fuel cap) with a blow gun on the air compressor hose. One way to test this would be to get it to the point of stalling out right away, like at the end of your video, then loosen the gas cap real quick, then try it again...if it goes longer before stalling then that has to be it.
Does it matter at all how full the fuel tank is? When I have had problems with cracked fuel lines in the tank, it would run fine until it got to the point of sucking air, then it would act just the same as yours again...I know you have replaced your lines though...was just curious if fuel level makes any difference...

 

Can you get the compression tested, or pull the cylinder for a better look. At least look at the intake side. I had a blown saw doing the same thing yours is. Started, revved, died in the cut

 

Grip the handle tightly, swing it back and forth then around over your head then let go of it and let it fly into the ravine. Fixed, now go buy a new saw.

 

Wow, rough crowd today!

 

How did you determine the first carb was shot? So little hours I’d think it may want to be cleaned and soft goods replaced at most.

Did the saw run like that before you changed everything?

And is the carb oem or a cheapy?
Cheapies for me run pretty well most of the time, but now and again I get one that doesn’t work.

Maybe try to clean and rebuild the original carb and see how that goes

 

It sure acts like its starving for gas, for whatever reason. The bad coil issues I've dealt with, the saw dies like you've turned it off (kill switch), and doesn't restart until it cools off. Your saw will idle indefinitely and hot restart immediately.
I know that you've replaced the fuel cap but after cracking open the cap, will it run longer before dying (preferably with a half tank of fuel or less)? Free and easy to test. I've fixed two saws this winter with the same symptoms. The fuel tanks weren't venting. Husqvarnas, neither vented through the cap by design.
Aggravating I know.

 

These are "yellow Huskys"...many/most of the parts say Husqvarna right on them...