Stihl MS171 - Will only start with carb cleaner then stops

[andrewjmdata]

My Stihl MS171 chainsaw has never had any problems starting before. Now it just won't start. Admittedly it was left for a while with old fuel in. I changed the fuel, the air filter is clean, there is a spark from the spark plug. Also checked the fuel filter in the tank and that's fine.

I bought some carb cleaner and sprayed into, what I think is the choke. It started and ran for about 10-15 seconds then stopped. I managed to rev it a couple of times but again it stopped.

While I have an idea how a petrol engine works, I'm no mechanic. Was thinking to take off the carburettor but can't see how and can't find any help online.

Any ideas?

Many thanks

Andrew

 

[furb]

Don’t run your saw on carb cleaner. Try taking the carb apart and clean it. Don’t use compressed air anywhere on the carb.

 

[andrewjmdata]

That was a quick reply. Do you know of any instructions on how to take it apart?

Thanks!

Andrew

 

[furb]

I think it’s the two screws on the side of the rear handle, two nuts on the air filter base, the choke and throttle linkage and it should pull off. Take pictures as you go so you remember how it goes back together.

 

[andrewjmdata]

I think it’s the two screws on the side of the rear handle, two nuts on the air filter base, the choke and throttle linkage and it should pull off. Take pictures as you go so you remember how it goes back together.

I'll give it a go. Thanks!

 

[andrewjmdata]

This is good. Am pretty sure my model is same as MS211.

 

[furb]

FYI, if you have a 6 in 1 screw driver you should be able to pull one bit out and use it as a nut driver on the carb nuts.

 

[Arrowhead]

Put a new carb and fuel filter on it. These carbs are very inexpensive.

 

[andrewjmdata]

Now got carb out and will replace with a new one. Thanks all!
Andrew

 

[CausticUC]

If changing your carb does not help, you probably have a crack in your fuel line somewhere.

These type of in tank pickup will harden and crack. I keep 5 or so around for my saws to have on hand.

 

[lone wolf]

Now got carb out and will replace with a new one. Thanks all!
Andrew

Check the fuel ine for leaks or cracks like already mentioned,if you have a pressure tester you only need to pop the filter off ,you can leave it in place for a test in that case.

 

[ElevatorGuy]

I bought a $9 knock off stihl carb on amazon a few years back for my 180c. It was doing the same thing and the carb did the trick.

 

[andrewjmdata]

Replaced carb, works fine now

Thanks all.