Idle issues Stihl MS271 HELP

[Sparky 46]

Help, my Stihl MS271 won't idle and dies at idle. New Carb, fuel filter, cleaned muffler,no ethanol fuel only, tried adjusting. Rebuilt the original Carb. and tried that with no luck and exactly the same outcome as the new carb. No matter what we do it simply dies when it goes back to idle. What am I and my friend missing, we are stumped. We are both fix anything for everyone mechanics and stumped. My first time posting here and happy to join this community, Thank you all !!!

 

[Sparky 46]

Help, my Stihl MS271 won't idle and dies at idle. New Carb, fuel filter, cleaned muffler,no ethanol fuel only, tried adjusting. Rebuilt the original Carb. and tried that with no luck and exactly the same outcome as the new carb. No matter what we do it simply dies when it goes back to idle. What am I and my friend missing, we are stumped. We are both fix anything for everyone mechanics and stumped. My first time posting here and happy to join this community, Thank you all !!!

I should add it's not a new saw but has relatively low hours and never seen ethanol fuel. Not rode hard and put away wet. Thanks

 

[hacskaroly]

my Stihl MS271 won't idle and dies at idle.

Welcome to the forums! Possibly an air leak between the carb and cylinder or either of the oil seals. You can get the saw running and then spray non-flammable brake cleaner around those areas, and if there is a leak then the saw will shut down (with no damage), though you could also use (but I don't recommend) carb cleaner which is flammable and if there is a leak, the saw will race - not the greatest thing. Either way you will know if you have an air leak.

Also, the on/off/choke lever is easy to bend if you (or the previous owner) wrench on it, possible that when blipping the trigger it actually connects the contacts to shut it off. I had to replace one of mine because of that.

 

[Agent Smith]

Another thing to check is the transfer covers. These and the 291's are known for the covers coming loose at the seam where stihl glues, epoxies or whatever they use to attach them to the cylinder.

 

[hacskaroly]

Another thing to check is the transfer covers. These and the 291's are known for the covers coming loose at the seam where stihl glues, epoxies or whatever they use to attach them to the cylinder.

Yes, that is a good point, had a customer that was using a 311 to mill and got it so hot the transfer cover blew off...JB Weld to the rescue!! That is one thing I like about Husky cylinders, they put screws in their removable transfers!

 

[Agent Smith]

Yes, that is a good point, had a customer that was using a 311 to mill and got it so hot the transfer cover blew off...JB Weld to the rescue!! That is one thing I like about Husky cylinders, they put screws in their removable transfers!

I did see an ebay aftermarket 291 top end kit recently where the transfer covers were screwed on so kudos to the aftermarket world for going that route. Unless i missed them, it'd be nice if husqvarna sold the xfer cap gaskets by themselves. I've had make a few out of gasket material before. Its tedious work

 

[lehman live edge slab]

Yes the ms 271/291 and 311/391 both had some experience with loose covers but I’m pretty sure the newer ones don’t have covers i know there was some updates

 

[lehman live edge slab]

The two different styles, one has transfer covers and a clamp on boot, the other no covers and screw down style intake boot like a 362.

 

[hacskaroly]

The two different styles, one has transfer covers and a clamp on boot, the other no covers and screw down style intake boot like a 362.

I have only seen the newer style, both of mine have that. Was the other one for earlier 271s or 270s?

 

[lehman live edge slab]

Also i personally don’t think jb weld will do a sufficient job on the covers. Maybe some form of devcon will but jb i personally don’t think will do it. If I found a set of loose covers on a 271 or the like I’d be tempted to clean the epoxy off and weld them on. Even if you used Hobart aluminum stick to weld them in a few spots then sealed with jb weld so it’s just being used for sealer not strength.

 

[lehman live edge slab]

I have only seen the newer style, both of mine have that. Was the other one for earlier 271s or 270s?

Not 100% sure I’ve worked on both some in 311/391 and 271/291 forms. And these are the 271-291 styles no 270 in this that’s different looking all together just like a 280

 

[lehman live edge slab]

Ms 270/280 style cylinder, the ms 280 was the first crack at solenoid control carb. Had an adjustable low speed if i remember and a solenoid tuned high jet. Pre mtronic

 

[lehman live edge slab]

I have only seen the newer style, both of mine have that. Was the other one for earlier 271s or 270s?

I do believe the clamp on intake/glued transfer covers was the old style and they updated to the 362 style screw on boot with no covers to end the issue of them leaking air

 

[Sparky 46]

Welcome to the forums! Possibly an air leak between the carb and cylinder or either of the oil seals. You can get the saw running and then spray non-flammable brake cleaner around those areas, and if there is a leak then the saw will shut down (with no damage), though you could also use (but I don't recommend) carb cleaner which is flammable and if there is a leak, the saw will race - not the greatest thing. Either way you will know if you have an air leak.

Also, the on/off/choke lever is easy to bend if you (or the previous owner) wrench on it, possible that when blipping the trigger it actually connects the contacts to shut it off. I had to replace one of mine because of that.

Thank you I'll go through it.

 

[Sparky 46]

Thank you everyone ! I figured it was an air leak thinning the mixture but didn't know where the trouble points were. Lots of talk about JB weld and found something much better. POR 15 makes a body putty in a tube that air drys hard as a rock and even sticks to plastic fuel tanks. So hard you can't sand it. Find its the best repair putty around but you've got it get it correct the first time, no sanding or smoothing it out after it drys.

 

[lehman live edge slab]

Don’t honestly know how it can be so hard you can’t form it. Honestly depending how old it is you won’t need to worry about the transfer covers because not all have them