1964 speeditwin 28 - fuel problem, gas leaking out of carb

garboj

Cadet
Joined
Sep 26, 2006
Messages
16
Outboard was running great after full electrical rebuild (and gearcase), but motor died today while on LI sound. (glad i brought the kicker, as always). symtoms: plugs are dry. not fouled. good spark to both plugs. no gas.

when i squeeze the bulb, gas pours out of the carb. NOT out of the throat of the carb, but out of this hole in the front of the carb. if you know this carb, there is a hole just to the right of the low speed adjuster ,and to the left of the high speed adjuster. looking at the carb, the hole is basically right between the two carb adjustments.

at first i thought: "stuck float", but that seems wrong, since if it was the float stuck open, there be too much gas to the plugs, and not none. if float was stuck closed, no gas would flow when the bulb was squeezed. so, is this a fuel pump failure? i haven't begun to tear it down yet - i know somebody out their knows exactly whats wrong and will save me some time... don't want to pull the carb off if this is fuel pump diaphram or something... thanks in advance.
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: 1964 speeditwin 28 - fuel problem, gas leaking out of carb

Still sounds like a stuck float because if your plugs are dry it is stuck and not letting fuel out. When you pump the ball then the fuel is forced into the carb but has nowhere to go except out of this weephole.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: 1964 speeditwin 28 - fuel problem, gas leaking out of carb

Why would you suspect the fuel pump? That has nothing to do with it. Get a carb repair kit from a dealer (that will get you a new fuel-proof float) and clean and inspect the carburetor.
 

garboj

Cadet
Joined
Sep 26, 2006
Messages
16
Re: 1964 speeditwin 28 - fuel problem, gas leaking out of carb

thanks for your replies gentlemen.

yeah, i figured it was either the float or the fuel pump, and since i don't know the precise symptoms of failure of those systems on this ob, i had to consider both as possible causes.

i knew a stuck float would stop gas from entering the carb, but wondered why gas was flowing out of this overflow? hole when the bulb was sqeezed. i imagined a cracked diaphram in the fuel pump might lead to the symptom of the fuel bulb staying squeezable, and blowing gas past some check valve instead of into the carb....

i will post my findings after inspection later today.
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: 1964 speeditwin 28 - fuel problem, gas leaking out of carb

If the engine dies while hot it takes suprisingly little time to evaporate off the spark plugs.

The only possible reasons to have fuel coming out of the bowl vent (that's what that hole is) is a sunk float, a float stuck in the down position, or a leak in the needle & seat that the float operates on.
 
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