# Stihl fs74 leaking fuel out of the carburetor



## redforeman450 (Aug 31, 2015)

I store the trimmer in the vertical position. I've tried stirring it vertically, loosening the fuel cap when I'm finished using it, I cleaned and rebuilt the carburetor. Gas still seaps out of the air filter, emptying the fuel tank in a couple of days. Where do I start? Thanks.


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## ANewSawyer (Sep 1, 2015)

Fuel entering the carb should have to go past the metering lever and the spring that holds it down. It sounds like simple fuel pressure to me. Does it happen when stored horizontally?


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## backhoelover (Sep 2, 2015)

Need to pressure test carb also 


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## redforeman450 (Sep 2, 2015)

I fouled up my first post, I meant to say that it leaked when stored horizontally also. How does one go about pressure testing a carb?


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## backhoelover (Sep 2, 2015)

I made my own out of blood pressure tester a 15 psi gauge brass t and some fitting will send a pic when I get home 


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## backhoelover (Sep 2, 2015)

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## backhoelover (Sep 2, 2015)

I love that thing I have about 6 different ends the end on its test Briggs push mower carbs that have the primer on the side 


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## backhoelover (Sep 2, 2015)

Thank the old lady she was nice enough to find it in my shop and take a pic for us when I get home I'll send you the Stihl carb manual I think it goes over pressure testing carbs 


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## Greenthorn (Sep 2, 2015)

Carb needle float is not seating correctly.


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## redforeman450 (Sep 2, 2015)

Thanks for all the replies, looks like I'll give the needle and seat another going over this weekend. 

Does the fuel tank vent through the cap, if so, could the cap be faulty?


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## backhoelover (Sep 2, 2015)

these might help


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## redforeman450 (Sep 6, 2015)

Thanks for all the advice. I put a gas cap from a spare fs74 on and that solved the issue.


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## ANewSawyer (Sep 6, 2015)

Hah, sometimes it is something simple.


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## backhoelover (Sep 6, 2015)

i never that lucky lol


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## backhoelover (Sep 6, 2015)

i almost forgot i told you i was going to send stihl carb manuals, kinda too late lol


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