Briggs and Stratton Classic Carburetor Leaking Gas x2

Gorrillasnot

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
I am working on 2 push mowers. 1 with a 3.5hp and the other is 5hp.
Both needed a carb clean and new diaphragm and gasket..No problem I thought. Seemed like an easy enough job.
I pulled the carb's, cleaned them, installed new diaphragm and gasket, and o-ring that goes to intake tube.
Problem is now both carburetors are leaking fuel around the base where they are attached to the fuel tank.
Asked a local mower shop and the guy said its common on older mowers, most likely a warped carburetor. he said they don't even mess with cleaning/rebuilding carburetors anymore.. They replace them with amazon or ebay one's.

I don't like to give in that easily (or give china my money)..is there any tips or tricks you all know of to get the carbs to stop leaking?

thanks
 

sgkent

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
or warped fuel tank. You need to check both the carb base and tank base in like an [X] with a straight edge.
 

slomo

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
Sure the cap is not the issue? See if the cap still has the gasket. Swap caps around if they fit. Strange this is on 2 mowers.......
 

Hammermechanicman

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
Over torqued screws can warp carbs and tanks. Sometimes doubling up the gasket helps
 

Gorrillasnot

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
It's not the gas cap..I checked closely and it definitely looks like its coming from the base of the carburetor on the inbound side.
I did snug up the screws good and tight..maybe I overdid it.
If I take it back apart can the gasket and diaphragm be reused or would I need new again?

thanks everyone
 

slomo

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
If I take it back apart can the gasket and diaphragm be reused or would I need new again?
Flatten, polish, sand or lap the carb mount area as best as you can. You can reuse the carb diaphragm. No guaranty it will not seal proper. Try it out. Another reason NOT to over torque carb screws and such on mowers.

On paper gaskets and diaphragms, I put a thin layer of 100% silicon grease (Magic Lube) all over them. Paper gaskets don't stick as in easy removal and for testing like this. Magic Lube is great for plumbing repairs and any O-ring fixes you have. WIll not wash off in chlorinated water. Made for the swimming pool industry as in pump basket O-rings and the like.

1652465281825.png
 

Gorrillasnot

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
I finally got them to seal up.. I sanded the mounting pad on the tank.
I'll look into getting some magic lube..I noticed on amazon there is 2 different versions. A red tube (silicone) and blue tube (teflon) which version would be best?

thanks
 

slomo

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  • / Briggs and Stratton Classic Carburetor Leaking Gas x2
I finally got them to seal up.. I sanded the mounting pad on the tank.
I'll look into getting some magic lube..I noticed on amazon there is 2 different versions. A red tube (silicone) and blue tube (teflon) which version would be best?

thanks
The one in the picture. You can also get it at your local swimming pool supply store, if you have one. All are 100% silicone so not to harm any o-rings like petroleum greases do.

It's good for o-rings, fishing reels (silicone is anti-water slash moisture), long term gun storage, mower gaskets or any place you need a lube that stays put.
 
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