# Stihl FS66 Carburetor. Any others that will work or anyway to retrofit primer?



## oldjonsered (Jun 25, 2016)

My still FS66 is in amazing condition and runs great. Only problem I have is it seems like I always have issues with it priming as it has no primer bulb on this old model..It doesn't get used a lot as I have it set up with a blade and only use it for my heavy brush cutting. I was just wondering if there was something in particular to look for to resolve this issue...or the other thing I though was maybe swap a new carb with a primer bulb onto it.


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## backhoelover (Jun 25, 2016)

a leaking crankseal can cause this problem


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## oldjonsered (Jun 26, 2016)

backhoelover said:


> a leaking crankseal can cause this problem


I'm curious, how would a leaking crank seal cause this and how would I be able to check if it's bad?


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## backhoelover (Jun 26, 2016)

carb runs of the vacuum of the crankscase if vacuum gets low from a leak the fuel pump will not pump enough fuel to the metering side of the carb


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## backhoelover (Jun 26, 2016)

this should cover it


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## backhoelover (Jun 26, 2016)

the carb you have is a wt 112 walbro. that is the only listed carb for that model and its 100.00


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## backhoelover (Jun 26, 2016)

here is stihl carb manual. will teach you how to check carbs


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## backhoelover (Jun 26, 2016)

have you check the diaphragms yet. they should not be stiff and the little lever that the needle and spring hook to need to be flush with the body


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## backhoelover (Jun 26, 2016)

here is the walbro service manual also


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## oldjonsered (Jun 28, 2016)

backhoelover said:


> here is the walbro service manual also


Thank you for all the information! Do you think maybe I should just start by throwing a rebuild kit in the carb and see if that works? This brush cutter sat for a long time and I tore the carb apart and cleaned it to get it up and running and it ran fine originally....It doesn't get used much and after sitting thats when these problems arose again. Are the carb kits from Stens any good? I've had good luck with parts from steps in the past but haven't bought any in quite some time.


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## Cycledude (Jul 13, 2016)

Hopefully you've been using only premium grade gas which contains no ethanol, it costs a little more but it doesn't cause the problems that ethanol causes


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