I have tried everything but can’t get my chainsaw to run properly and looking for help. I have a Poulan Pro 42cc 18” model 4218a it is 3-5 years old but has run for only 3-4 hours at most so brand new. Since it sat around unused the carb was shot so I have done the follow work. New carb New fuel line New fuel filter New vented gas cap New mixed gas I have adjusted the carb and I can start it with about 10 pulls and it idles fine. I pull the trigger and it seems fine. However I get halfway through a 15” log and it dies. I can restart the saw with 1 pull no choke and it idles fine but when I start in the log again it immediately dies. Again 1 pull and it starts again. This goes on for the rest of the day 1 pull starts and give it gas and it dies at high speed. It seems it will idle forever fine but it just will not cut anymore. I have messed around with the carb settings for hours without luck. The only other thoughts I had were that the replacement fuel filter from the small engine shop I bought is black plastic with a cloth type material. The original was a white ceramic type. The new fuel line was slightly thinner than what was on it but I thought that the old line may have swelled from the gas in the fuel line over the years. Any suggestions on why I can’t run this saw for more than 5 minutes?
I have a couple of those 4218A's...usually when they start and run then die in the cut later on its because the fuel line in the tank has a crack in it...if I fill the tank up to the top it will run for awhile again, but if you are sure your line is good, then that's not it. My MS290 would quit after it got hot...coil was bad...but it would not restart right away like yours does. Have you tried opening the fuel screw up more? Sure sounds like its running out of fuel...new carb bad?
When I adjust the H screw further out it stutters and dies and then I can not get it started unless I turn the H screw back in. Currently the H screw has to be out somewhere around 2 1/2 to 3 turns. I was thinking that maybe the gas line is actually too small and I need to get the next size up. It went into the tank pretty easy and I thought it actually might not seal tight and leak fuel. Any thoughts on this (size of the fuel line)?? Also thoughts on the fuel filter not being ceramic??
Its certainly possible this is causing issues...seems unlikely though...hard to say from Ohio Will it run longer at say half throttle?
Sounds to me like your next step may be a new coil. Was the replacement fuel line and filter the same size as oem? Pulling the muffler is an easy thing to do, so start there, like mentioned above. Take a pic of the piston skirt and ring and share it with us. If your carb is not adjusted properly, the piston could be scored and causing your problems.
Doesn’t look too bad, so I’d count that out and say you aren’t tuning too lean or it would score. Symptoms sound like the tank is running out of ventilation. When it starts cutting out, have you tried to carefully unscrew the cap a little and see it it perks back up? Or can you try that safely? I know you have a new cap listed but maybe it can’t keep up with what the saw needs. The only things left in my head are fuel and spark. It almost has to be fuel delivery, or ignition. I agree that the coil shouldn’t cool down that quick for a restart if it was failing. So, left with carb or fuel feed to it.
I am going to get a larger diameter fuel line since it seems that it may be fuel delivery as the problem. Any comments on whether a cotton fuel filter is OK or is plastic (or is it ceramic) better?? I can pick up a new filter as well. The white with silver metal is what was originally in the tank but the guy at the store gave me the black one which I have currently in my saw.
I did not replace the plug but I did pull it and cleaned it off. It had some carbon on it and blew it off with carb cleaner. Did not think to replace a plug with 3 hours of use on it. Any comments on changing the plug? Also it will run at half throttle no problem. Ran it like that for 10 minutes. It is when that second air inlet opens at full throttle that seems to cause the issue.
How's your air filter, is it new or old? I had a problem with my 310 last fall, it would stop after cutting for 20 minutes. I took it to two dealers, they both said there was nothing wrong with it but when I brought it home, it would stop running after cutting for 20 minutes. I ended up buying a parts saw (290) I took the new carb out of that and put it in the 310, it has been running fine since. The elevation where both Stihl dealers are is 377 feet, our property where I cut is just over 1000 feet. Before I bought the parts saw, I was so pizzed off at the 310, I bought a brand new 311. Buy a new saw and the old one will start working!
Well, its certainly running out of fuel then...I'd try the correct fuel filter and line as you plan to do...go from there
And I wouldn’t rule out you’ve sucked old fuel tank mud into the metering valve filter on the carb. That is a prime spot to loose fuel flow at full throttle. I’ve come across a few that acted that way and the screen was plugged. Surprised it could even idle. Here’s one from an 026, plastered vs new Here’s one from an 020 I rebuilt but neglected to rinse the tank before PMT
