gas leak

[Uncle Fuzzy]

I have a 2004 225hp four stroke. Lately I've noticed a gas slick on the water when I come in to the dock and lift the engine up. Some times the slick is 20ft in diameter and seems to drip off the leg above the prop. Is anyone else having this issue. I just had the seals on the steering and the lifting rams all replaced so i don't think it is hydraulic fuid

[robert graham]

I'd remove the upper cowl and carefully inspect all fuel system and lines for leaks....Before you have a fire!

[rmartin00]

gas leaks

I have the same problem with a 2007 Yamaha F250 four stroke. I have checked the system and lines for leaks with the engine running but could not find any. The gas appears to only leak when the engine is stopped and tilted up. Did you ever find the problem?

[rodbolt17]

smell test it.
trim fluid,gear oil,steering fluid and gas all look about the same on the water.
about the only way to leak gas out of the exaust would be either a massive flooding of the VST or a stuck open injector. both will cause running issues.

[rmartin00]

gas leak

Thanks for your reply. The engine runs fine. The only thing I notice is when the engine first starts it seems to rev a little high then idles. I am sure the leak is Gasoline. When the engine is raised the Gasoline drips off above the anti-cavitation plate.

I do not know what the VST is but when I changed the gas/water separator filter I pulled the wire off under the filter bowl and the whole sensor came out of the bowl. I had to replace the filter bowl. When I finished replacing the gas filters the bulb in the gas line would never get firm. Could that be a sign of the problem?

[boscoe99]

Thanks for your reply. The engine runs fine. The only thing I notice is when the engine first starts it seems to rev a little high then idles. I am sure the leak is Gasoline. When the engine is raised the Gasoline drips off above the anti-cavitation plate.

I do not know what the VST is but when I changed the gas/water separator filter I pulled the wire off under the filter bowl and the whole sensor came out of the bowl. I had to replace the filter bowl. When I finished replacing the gas filters the bulb in the gas line would never get firm. Could that be a sign of the problem?

Yep. That might indicate there is a leak in the filter assembly. Easy enough to cross thread the bowl onto the filter housing. That or a hose has been split when removing or installing it onto the filter housing.

Pump the hell out of the primer ball while observing the primary fuel filter.

[TownsendsFJR1300]

Thanks for your reply. The engine runs fine. The only thing I notice is when the engine first starts it seems to rev a little high then idles. I am sure the leak is Gasoline. When the engine is raised the Gasoline drips off above the anti-cavitation plate.

I do not know what the VST is but when I changed the gas/water separator filter I pulled the wire off under the filter bowl and the whole sensor came out of the bowl. I had to replace the filter bowl. When I finished replacing the gas filters the bulb in the gas line would never get firm. Could that be a sign of the problem?

There should also be an o-ring up inside the main filter mount, the cup would screw into it. If it fell out, it'd leak.

Also, ethonol tends to make that plastic cup expand and make it difficult to install fully (and fully seat).

[rmartin00]

gas leak

Thanks for the help. There are no leaks at the bowl or any visible hose. The old bowl had been cross threaded and very difficult to remove. I was pretty careful when I installed the new bowl not to cross thread it. I also put new cable ties on the hoses at all connections. I do think I need a new gas bulb. The back flow valve on the bulb is not closing. When I was squeezing the bulb, I could hear the fuel going back into the gas tank on the boat. The gas appears to be coming out the exhaust. There is no gas inside the lower cowling. It only leaks after the motor is run and tilted up. I talked with a service tech who is familiar with the Yamaha. He said this motor sometimes leaks from the throttle. Does that ring a bell with anyone?

[boscoe99]

For best results the primer ball it needs to be held vertically with the outlet on top.

Otherwise, a check valve might not be checking.

[rmartin00]

Gas Leak

Thanks boscoe99. That makes sense to have gravity working to help seat the check valve. I could see some air bubbles in the filter bowl when I squeezed the primer bulb but it would never get hard. When the bulb got firm the gas was going back into the tank. I think ethanol in the gas may have destroyed the valve seat in the primer bulb.

[rmartin00]

Gas leak

I was wrong. The Yamaha Service tech checked the motor this AM. He said the leak is not Gas it is oil. The power head and foot have to be separated to replace an oil seal, all day job about $1000.00. I do have a question for the forum.

The leak was only noticeable after the engine ran and then tilted up? Looks like oil would leak continually?

[boscoe99]

The seal and/or the crank shaft itself gets worn at the seal to crankshaft interface. Yamaha provides a speedy sleeve that the mechanic will press onto the crankshaft. It is a thin stainless steel band that acts as a wear strip. For the money you are paying I presume that he is also installing a new oil pump and oil pump seals.

The leak might have been so slight that it was never noticed while the motor was running. However, when you stop the oil spreads out on the surface of the water and is much more noticeable. A small bit of oil can look like the Exxon Valdez oil spill.

Now when he opens up the motor for surgery don't be surprised if the dreaded Yamaha F200/F225 corrosion issue rears its ugly head. You might want to be prepared to install new updated mid-section components.

B.O.A.T. Break Out Another Thousand. Or more.

[rmartin00]

gas/oil leak

Thanks for the explanation and heads up boscoe99. I did tell him to replace the water pump. It has never been replaced. I'll talk to him about the oil pump. The motor doesn't have more than 400 hours on it. Thanks Robert Martin

[99yam40]

A 10 year old motor with only 400 hours and never had water pump replaced, do not be surprised if there is a problem dropping lower unit also.
They need to be pulled and lubed up more often than 10 years.

Shaft and bolts can stick and cause major problems

[rodbolt17]

snow job?
BS job?
baby needs a new pair of shoes job?

I will post this for the SECOND time.
the ONLY two ways you will ever get gas in the EX is
1 the VST needle fails to seal and severly floods the motor.
2 an injector is seriously leaking.
both will cause major running issues.

that's why I said smell test it.
in rare occasions I will taste test it but it costs extra.

UNLIKE some of the smaller 4 strokes there is NO WAY to place fuel in the oil or ex on the v6 200/225 4 stroke other than the VST into the airbox OR an injector leaking.

the oil pump seal is a dumbass idea as it wont care if the engine is up,down or whatever.

why is common sense not so common???????

typically we see the speedi sleeve at 800-1200 hours.
400 is a bit low for wearing out the seal surfaces.