C_Spray
Charter Member
I pulled into a marina on Sunday, and one engine would not idle correctly. The engine smelled rich, so after we tied up, I opened the hatch and went to fire it up. BIG MISTAKE. I should have gone in and sniffed first. As soon as I turned the key and the pumps came on, there was a small, fine-spray geyser of gasoline spraying straight up! Fortunately, it did not ignite. I got everyone off the boat, got out the handheld extiguisher, turned on the blowers and closed the cabin door. There was several ounces of gas in the intake manifold and a film of gas residue all over the top of the engine. Bit by bit we got it evacuated and all cleaned up, and then went looking for the leak.
The Schrader valve on the fuel rail (used by mechanics to check the fuel pressure) was the culprit. It was leaking, and the plastic cap on it was no match for the 50 psi the pumps were putting out. We replaced the valve with a small fuel pressure gauge that a friend had, and counted our lucky stars.
Here's the kicker: I checked out the offending Schrader valve this morning, and it turns out the actual valve core had backed out about half a turn! This engine had about 440 hours on it.
I am going to re-install the valve, check to make sure the one on the other engine is tight, and install METAL valve caps on both valves. I was considering simply replacing the valve with a 1/8 npt port plug, but with my luck, I will need to check fuel pressure the next time I run.
All EFI engine owners should do themselves a favor: Go out and buy or borrow a valve core tool, check the Schrader valve(s) on your engine's fuel rails, and make sure that you have metal valve caps on them. You can get metal tire valve caps at most car parts stores.
I'm still trying to determine why I never heard the gas fume detector in the bilge go off. (It was working a last weekend when we refueled in a headwind.) It might have been the wind and engine noise while we were running, but it was silent at the docks. Time to get that checked for sure!
I feel very lucky...
The Schrader valve on the fuel rail (used by mechanics to check the fuel pressure) was the culprit. It was leaking, and the plastic cap on it was no match for the 50 psi the pumps were putting out. We replaced the valve with a small fuel pressure gauge that a friend had, and counted our lucky stars.
Here's the kicker: I checked out the offending Schrader valve this morning, and it turns out the actual valve core had backed out about half a turn! This engine had about 440 hours on it.
I am going to re-install the valve, check to make sure the one on the other engine is tight, and install METAL valve caps on both valves. I was considering simply replacing the valve with a 1/8 npt port plug, but with my luck, I will need to check fuel pressure the next time I run.
All EFI engine owners should do themselves a favor: Go out and buy or borrow a valve core tool, check the Schrader valve(s) on your engine's fuel rails, and make sure that you have metal valve caps on them. You can get metal tire valve caps at most car parts stores.
I'm still trying to determine why I never heard the gas fume detector in the bilge go off. (It was working a last weekend when we refueled in a headwind.) It might have been the wind and engine noise while we were running, but it was silent at the docks. Time to get that checked for sure!
I feel very lucky...
Last edited:
