Fuel pouring out vapor separator (not while fueling)

[Kelpiesgmc]

I just recently dropped both tanks and had them "boiled". Got them back in with all new hoses and two new vapor separators (one per tank routed independently). When I did the first fuel fill up the vapor separators didn't stop the fuel pump and I over filled the tanks and gas started pouring out the vapor separators. Huge bummer. I'd tested them both before installing by hooking up a tube and filling the tube with water. Both stopped water from coming out the output valve and both held water without leaking.

The coach ran like hell for the first few minutes and I had to remove the gas cap for extra ventilation just to get home from the gas station.

Days later I was walking by the coach and I smelled a strong whiff of gas. Inspected everything and no leaks— then I looked at the vapor separators. They were STILL dripping fuel even roughly two weeks later.

I figured the vent lines and fuel fill must still be full of gas so I ran the Onan for 1/2 hour.

Then I shut off the Onan and checked the vapor separators. The video shows what I saw.
Gas was POURING out the vapor separators.

 

[Richard RV]

I just recently dropped both tanks and had them "boiled". Got them back in with all new hoses and two new vapor separators (one per tank routed independently). When I did the first fuel fill up the vapor separators didn't stop the fuel pump and I over filled the tanks and gas started pouring out the vapor separators. Huge bummer. I'd tested them both before installing by hooking up a tube and filling the tube with water. Both stopped water from coming out the output valve and both held water without leaking.

The coach ran like hell for the first few minutes and I had to remove the gas cap for extra ventilation just to get home from the gas station.

Days later I was walking by the coach and I smelled a strong whiff of gas. Inspected everything and no leaks— then I looked at the vapor separators. They were STILL dripping fuel even roughly two weeks later.

I figured the vent lines and fuel fill must still be full of gas so I ran the Onan for 1/2 hour.

Then I shut off the Onan and checked the vapor separators. The video shows what I saw.
Gas was POURING out the vapor separators.

That's a weird one. The vent lines and vapor separator(s) are closed systems, open only at the ends at the tank and canister. For that amount of fuel to be coming out at the separator there'd have to be a hose not connected or the separator has split.

Remove the separators and investigate.

 

[Don Jaksa]

Glad to hear the Onan is still running

 

[tmsnyder]

That's a weird one. The vent lines and vapor separator(s) are closed systems, open only at the ends at the tank and canister. For that amount of fuel to be coming out at the separator there'd have to be a hose not connected or the separator has split.

Remove the separators and investigate.

I love how the system intended to prevent pollution actually creates a ton of pollution. Was this designed by the government?

 

[RF_Burns]

I would loosen the filler cap to relieve pressure in the tanks. The vents are openings at the very top of the tanks so you have liquid fuel right to the very top for liquid to come out the vent lines.

Pressure in the tanks has pushed fuel up the vent lines and the liquid float sealed off in the vapour separator causing pressure to increase more and maybe cracked the separator causing the leak.

 

[tyler]

My only thought is the plumbing got mixed up on re-assembly - the fuel separators do not go inline for the fuel fill vent, they go inline for the charcoal canister vent line. Seems the only way that much gas can be present is if it is on the wrong line.