Mercury Bigfoot 50HP 4-stroke - leaks gas from around carb and rough or won't run

niknik

Recruit
Joined
Jul 2, 2013
Messages
1
I have a 1998 50HP Mercury Bigfoot 4 stroke on my pontoon. I have a recurring problem with the fuel/carbs, it was supposed to be fixed 18 months ago with a carb rebuild but it's back.
If the engine starts it runs very lumpy and will cut out. As the engine is running or when stopped and I squeeze the primer bulb gas comes out from around the second carb from the top. Gas may be coming from other carbs too or from a hose as I cannot see behind the carb bodies.
I cannot take it back the dealer who fixed it as the are shut down as the owner retired. I am nervous about taking it to another dealer and forking out $100s of dollars.
Any ideas on what the problem could be? The previous fixed was supposed to be needle seating issue??? But I am not sure.

:mad:
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Re: Mercury Bigfoot 50HP 4-stroke - leaks gas from around carb and rough or won't run

First of all welcome to iboats :welcome: always good to have another boater aboard...

Any time you can squeeze the fuel primer bulb and gas comes out of the carb, you have a needle and seat issue and/or a float level misadjusted. I say fix the carbs with new carb kit(s) after a thorough cleaning and lower the float level(s). Too high a float level will cause gas to come out of the carb because the float can't shut off the incoming fuel. So I'd fix that and see what happens...
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Mercury Bigfoot 50HP 4-stroke - leaks gas from around carb and rough or won't run

What the above poster posted.
 
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