WildnCrazyGuy
ArboristSite Operative
Ok, I know this is NOT a trimmer forum, but please help! I've been fighting with my old Stihl FS36 trimmer and trying to figure out a gas leaking issue. It's not leaking drops, it's pouring out of, I think, the vent tube. At first I thought it was a bad fuel line or something like that. When I opened it up, checked all the fuel lines, they were all in excellent shape. I hate to say like brand new, but after about 17 years now and a little WD 40, they look like they were fitted and installed yesterday. Checked them for any signs of cracking and such.
So I did some due diligence and took it all apart, put it back together, making sure all the lines were connected firmly and properly, then turned it upside down again, and more gas running out. I can't see anything wrong with the vent tube assembly, which is where it looks like it's pouring from. I checked the rubber valve. It looks brand new and is just a piece of rubber that fits in its spot just fine. The coupling to that vent tube valve looks ok and I can't imagine how it could fail. It all looks good, but maybe I start here? Replace these two little things that don't look like they could even go bad?
My observations. Without firing the trimmer, if I turn it on it's side or upside down, it seems to build pressure and send the gas flowing. If I back the gas cap off, you can hear the pressure release hiss. Is it as simple as a bad gas cap? I can't see anywhere on the gas cap that looks bad, and it doesn't look to me like it's one of those that has a hole in it to function, maybe it is?
My other observation is when I do fire the trimmer, it's like the pressure builds up and then wants to kill the engine sometimes. After googling and searching and searching through here, I haven't specifically tried to slightly open the gas cap and see if it runs better. I will try that tonight and any other suggestions I hear from you guys. Is this an indication of a carb issue like needing a kit or cleaning or something? Something stuck open or closed and thus builds the pressure and makes the gas "pressurized" and have to run out the nearest exit? When I had it apart, I did spray through all the carb's exterior holes and such with carb cleaner.
Thanks in advance for advice. Before I spend much money on this old FS36 that's nearing the end of it's life, I wanted to try to make an educated guess at what to get to take a stab at fixing it, gas cap, carb kit, fuel hoses, etc. I'm waiting on a price from my Stihl dealer for some stuff including a new FS90. All things considered, if this thing weren't leaking gas everywhere it would still be a pretty good trimmer. Doesn't have very good compression, but still turns about 7500RPM, more than enough to trim some grass/weeds. I'd like to use it as a backup to my new one I'm looking at or most likely keep it at our other place to keep the weeds down instead of trucking something back and forth…
And if you're wondering why I turn it on it’s side, I use it to edge my driveway and such sometimes. It leaks gas all over me and it probably wouldn't take much to set the trimmer and me up in flames at that point. The muffler gets real hot. Again, thanks for the advice.
So I did some due diligence and took it all apart, put it back together, making sure all the lines were connected firmly and properly, then turned it upside down again, and more gas running out. I can't see anything wrong with the vent tube assembly, which is where it looks like it's pouring from. I checked the rubber valve. It looks brand new and is just a piece of rubber that fits in its spot just fine. The coupling to that vent tube valve looks ok and I can't imagine how it could fail. It all looks good, but maybe I start here? Replace these two little things that don't look like they could even go bad?
My observations. Without firing the trimmer, if I turn it on it's side or upside down, it seems to build pressure and send the gas flowing. If I back the gas cap off, you can hear the pressure release hiss. Is it as simple as a bad gas cap? I can't see anywhere on the gas cap that looks bad, and it doesn't look to me like it's one of those that has a hole in it to function, maybe it is?
My other observation is when I do fire the trimmer, it's like the pressure builds up and then wants to kill the engine sometimes. After googling and searching and searching through here, I haven't specifically tried to slightly open the gas cap and see if it runs better. I will try that tonight and any other suggestions I hear from you guys. Is this an indication of a carb issue like needing a kit or cleaning or something? Something stuck open or closed and thus builds the pressure and makes the gas "pressurized" and have to run out the nearest exit? When I had it apart, I did spray through all the carb's exterior holes and such with carb cleaner.
Thanks in advance for advice. Before I spend much money on this old FS36 that's nearing the end of it's life, I wanted to try to make an educated guess at what to get to take a stab at fixing it, gas cap, carb kit, fuel hoses, etc. I'm waiting on a price from my Stihl dealer for some stuff including a new FS90. All things considered, if this thing weren't leaking gas everywhere it would still be a pretty good trimmer. Doesn't have very good compression, but still turns about 7500RPM, more than enough to trim some grass/weeds. I'd like to use it as a backup to my new one I'm looking at or most likely keep it at our other place to keep the weeds down instead of trucking something back and forth…
And if you're wondering why I turn it on it’s side, I use it to edge my driveway and such sometimes. It leaks gas all over me and it probably wouldn't take much to set the trimmer and me up in flames at that point. The muffler gets real hot. Again, thanks for the advice.
, but... carb kit, throttle cable, fuel lines etc, and it lives again... $80 bill.... Hey, he was o.k. with that... Maybe he'll take he'll somewhere else next time..
