Yamaha F225 Intermittent Fuel Leak

[xperksx22]

I have been experiencing an intermittent fuel leak with my 2005 Yamaha F225. It only happens when the boat sits unused for a week or two. It seems like the fuel is coming out of the exhaust. It smells like gas. I had a mechanic come today and the boat didnt show any symptoms of a fuel leak and ran fine. I ran the boat on Sunday and had the fuel leak issue. Engine did not run good and was sputtering at low rpms. At this point i dont know what to do ? Any help is appreciated

[walleye1]

Check your engine oil, if it is over full and smells like gas it could be a fuel pump leaking in to crank case.

[99yam40]

I would not think a leak into the crankcase would send fuel out the exhaust, but a leaking injector could.
but then there should not be any rail pressure when the motor is not running to have a leak into the combustion chamber and out and exhaust valve either

[walleye1]

If a piston is in the rite spot gas can run straight through the exaust.

[99yam40]

If a piston is in the rite spot gas can run straight through the exaust.

on a 4 stroke?

[oldmako69]

This has quickly devolved into one of my fave threads......

A leaking low psi pump will be evidenced by fuel draining out the bottom of the cowling or by fuel pooling at the base of the engine. A leaking hi-psi hose can leak all it wants as long as its putting out the proper PSI at its outlet. At least that's how it is on my F225.

Unburnt fuel will come out of the exhaust. If the engine is running poorly it is not at all surprising that you smell unburnt fuel.

[walleye1]

I was thinking 2 stroke.

[xperksx22]

TownsendsFJR1300 I am seeing a sheen in the water once the engine is running.

[99yam40]

If you have a rough running motor and do not have a visible leak of fuel I would check injectors

[panasonic]

Seems to me that you don't have a fuel leak at all. Sounds like you have a running problem. Several cylinders are not firing intermittently (rough running) and the unburn fuel/air charge is going right out the exhaust into the water....

[walleye1]

Could have a fuel injector stuck open.

[marchmadness]

Pull the spark plug wires one at a time. Then check the plugs of the ones that cause no difference. Could be a simple spark plug. You can do the same for fuel injectors

[oldmako69]

Shoot em with an infrared temp gun while it's running.

[xperksx22]

Of course went down yesterday. Fired up the engine. Ran perfectly. No Fuel Leak. Tried to replicate the leak for a couple hours. Couldn't do it. Its driving me nuts.

[Oceanwave58]

I feel you pain. I have the same problem going on. 2003 yamaha 225. Its so frustrating. It's at the mechanics now and he can't find any leaks.