View Full Version : stihl fs 66 wont stay running

02-16-2005, 03:38 PM
when i went to start my fs 66 stihl the engine won't keep running. i had to prime the sparkplug manually to get it to start. i replaced the fuel filter and tested the fuel line where it plugs into the carb. strangely the fuel line stopped dripping when i tightened the gas cap. so i replaced the spark plug and when i looked at the new one after another priming there was some black material on it.
thank you in advance for thinking about today's project.

02-16-2005, 03:52 PM
check the vent on your gas cap. make sure it is clean of debris. Also, check with a spark tester and make sure there is good spark. Coils seem to go sometimes. I had a brand new Shindaiwa that needed a new coil. it would start and run but then wouldn't restart after I shut if off. It wouldn't hurt if you checked the spark arrestor and muffler. Make sure both are clean. And that your mix is at the correct ratio and new fuel.

02-17-2005, 03:27 PM
i tried that. the carb has a fitting under it that the gas line connects to. can i stay carb cleaner into that intake to clear any dirt? that maybe blocking the gas from reaching the carb. because it starts up right away when i prime the spark plug with gas.

02-17-2005, 03:33 PM
I don't know why you couldn't. Give it a try...worse comes to worse, get new lines. Is it running any better?

02-18-2005, 05:42 PM
check your fuel line from the filter in the tank to the carb and make sure its not cracked or holes in it. There is a diaphram in the carburator that may need to be replaced (couple of dollars). Its not that hard to take apart to check. Its like 4 screws. Just make sure you remember where the parts go when you put it back together.

02-18-2005, 07:04 PM
I just diagnosed my 027 today from a no run condition.
I would have to keep the choke on to keep this saw running, so assumed it was a messed up carb. Put in a rebuild kit, no difference. While trying to start it, I smelled gas and now saw a small puddle of it on the bench and around the gas tank. Low and behold, the line cracked right where it goes throught the plastic tank. Youhad to wiggle it to see the crack. Put a new one in and just like new. Try that.

02-18-2005, 08:52 PM
thanks for the posts. i will order a new fuel line and try that fix before i tackle the carb although the fuel line drips when i disconnect it from the carb.