Shop wants to replace carburetor--is it necessary?

[ZeroJunk]

I don't know what kind of saw it is. But, if you can see the butterfly and it is indeed closing down to a very small sliver and the linkage or idle speed screw is not keeping it open you do not need to test for a leak. You have one.

Nothing about the carb that can make it idle too fast other than the butterfly sticking too open.

 

[Cantdog]

I don't know what kind of saw it is. But, if you can see the butterfly and it is indeed closing down to a very small sliver and the linkage or idle speed screw is not keeping it open you do not need to test for a leak. You have one.

Nothing about the carb that can make it idle too fast other than the butterfly sticking too open.

True about the throttle plate and this can be caused by something as simple as the plate not being centered properly in the bore when the screw is tightened up and binding on one side or the other of the bore.