carb gas leak

[gorco]

I have mariner 115hp 1990 with a major fuel leak. The fuel hoses look fine.

I took the cover off of the air manifold ?? so that I could see into the carb throats. After a 10-20secs of idle, fuel started to puddle at the mouth of the bottom carburetor. It looked like the tube (?) protruding out of the bottom was full of gas. The other three caburetors appeared to be fine.

What could be the problem and the fix?

Thanks

Steve

 

[Barnacle_Bill]

Re: carb gas leak

Rebuild the carbs and check the float in that carb and be sure its not full of gas.

 

[j_martin]

Re: carb gas leak

The problem is that fuel was leaking past the needle valve in that carb, which could be from a bad valve, wrong float setting, a "sunk" float, (foam soaked in fuel, or a plastic float with a leak.) or chit in the valve.

You have to take the carb off and have a look. To do that, you need replacement gaskets as a minimum. You'll probably need either a needle and seat, or a float. If you're going to all that trouble, take them all off and go through them so you know they're right.

Unless time is gold, it's a 2 stage project. The gaskets are cheep, the parts are not so cheap, and cost stacks up quickly if you put too many in.

hope it helps
John

 

[gorco]

Re: carb gas leak

turned out to be a bad needle valve. Thanks for the help John.

-Steve

 

[gorco]

Re: carb gas leak

The bottom (4th) carb is leaking again and now, so is the 3rd. I cleaned the this morning, hoping it was dirt.

Could the issue be too much fuel pressure, forcing fuel past the needle valves.

Also, could it be that I'm putting needle valve in incorrectly?

Thanks