Gas leak at carb during start

Energy One

roedog

Member
When I go to start my 03 Mastiff after a week or so I get gas leaking out the carb if the bike does not start the first time. Not sure why this is? I crank the throttle 2-3 times, no choke before I start it. I notice maybe the carb may cough, backfire just a bit, but not all the time when it does not start the first time. After it starts I get no leakage at all, just the intial first start after sitting for a week or so. The bike does not seem like the timing is off and seems to run fine. So it's just puzzling me why I get the gas runoff around the carb.


Thanks for any info,

Roedog
 

LamboV12

Active Member
I would say stuck carb float. After sitting a while, the bowl level drops down, but the float is still in the up position. The sneeze in the carb means it's lean - and the twists in the throttle you give are going out the overflow instead of into the bowl.

When your riding and the float is moving up and down it can be fine, but when you let it sit the float is holding at the last position it was in when you shut her down.

Cheap and easy fix - about $10 and 30 minutes of time to change.
 

mcgroom

Well-Known Member
Is the gas coming out the overflow or pouring back out of the mouth of the carb?

Rebuilt a carb last week that would dump heavy into the mouth at times and barely spritz at other times.

The diaphram in the accelerator pump can go bad at times as well.

Just something to consider.
 
By twisting the throttle two to three times and getting a cough or backfire at start. Then seeing gas from the carb if it doesn't start.
By all of the symptoms you're describing, it sound as if you're squirting it too much by twisting the throttle so much and gas is going into the throat of the carb and intake making it too rich and flooding it. I'll bet you're smelling a lot gas fumes both either way too, aren't you?
Just twist it once to once and a half and try it again. Keep lowering number and amount of twist to the throttle if symptoms persist, until it works like it should.

Easy Fix! :2thumbs:

dead :cheers:
 

mobsta

Well-Known Member
i agree with dead on this one.also dont open your throttle at all while starting.just sayn what the hick do i know.:)
 
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