15 hp Johnson leaking fuel.

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Gatordenny

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Jun 2, 2013
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I was out running the boat and after killing the motor to do some fishing the boat reaked of fuel. I took the cowling off To look and noticed that fuel was leaking out from behind the choke. The motor would not start back up and had to have some one pick me up. After we let it sit for a while with the fuel line detached all the fuel leaked out and then I tried to start it again and it cranked right up. Why did this happen? Has anyone else had this happen? This is a 15 hp Johnson 2 stroke 1994.
 

Bosunsmate

Admiral
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Apr 7, 2012
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Re: 15 hp Johnson leaking fuel.

Stuck inlet valve needle or float in your carb.
You may need to change either or both
 

the machinist

Senior Chief Petty Officer
Joined
May 7, 2002
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711
Re: 15 hp Johnson leaking fuel.

When you pump the fuel primer bulb & it gets hard, does fuel leak out of the carb? If so that could be an indication the the float inlet needle is sticking open.
 

ddwilson

Petty Officer 2nd Class
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Apr 8, 2012
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116
Re: 15 hp Johnson leaking fuel.

float is sticking open, would suggest replacing the float, needle and seat. Should take care of the problem.
 

schematic

Lieutenant Junior Grade
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1,102
Re: 15 hp Johnson leaking fuel.

Although the fuel would not leak from behind the choke, it is also common for this model of carb to encounter a float bowl hairline crack. Very hard to see the crack, but will leak fuel. This can cause a rich mixture when sitting for a few minutes after a run (hot soak).
The top cover (plastic) also cracks on some models. This is usually visible.

Check the above posts as well and let us know...
 
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the machinist

Senior Chief Petty Officer
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May 7, 2002
Messages
711
Re: 15 hp Johnson leaking fuel.

On those later motors (post 93s) there was way less plastic carb top problems, it seems they changed the composition & design.
 
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