Hello again, this time I am trying to sort out a fuel venting problem.
I have 18' CC with a below deck fuel tank. When I rebuilt the boat and floor 2 years ago, I installed a recycled alum. gas tank below deck. After cleaning and coating the outside of the tank with coal-tar epoxy, All of the hose were installed new, with alcohol resistant marine grade fuel hoses. The fill and vent fittings come off the front of the tank and I installed a new pick-up in the rear of the tank. The hoses are about 5' long and run under the front deck and through a storage compartment under the front of the boat, then up to a fill fitting and a vent thru hull fitting with a screen. After the boat redo 2 years ago, the boat has worked great. The fuel tank has operated properly and the vent and fill worked as designed. My boat has been sitting for 8 months and I am now trying to get her back up and running.
The PROBLEM: now when I attempt to fill the tank with fuel, it acts as though the vent is inoperable. It takes a little fuel, then fills up the fill hose and out the top, the tank is a 24gal tank and it only has about 6 gals in it. Also, when I unscrew the fill cap, there is a release of pressurized fuel vapor. If I leave the fill cap on as it should, instead of vapor escaping from the vent as the fuel boils off and expands, liquid fuel is coming out of the vent fitting. I attempted to blow air into the fill by mouth, and there is a moderate amount of resistance/pressure in the tank. The trailer jack is up high so the boat is pitched nose up (to prevent the fuel from resting on the fill and vent openings). Because of the negative pressure created when running with the cap on and the vent not working properly, the motor doesn't run properly on the on-board tank. The motor runs great on a portable tank.
What I have done to problem shoot:
1) I took the vent hose off the tank and off the thru hull fitting. I removed the fitting and cleaned it up. (it was pretty clean when removed) I blew air through the hose and verified that it is not clogged.
2) I then placed a very small compressor on the vent and blew air in. When I blew air into the vent on the tank, air came out of the fill opening.
3) I then placed a 1 foot piece of vent hose on the vent opening. I then took a shop vac/blower and blew air into the fill opening. Liquid fuel came out of the vent hose and filled the catch can that I placed the hose into.
4) I also made sure that there was no kinks in the fuel lines. The fill hose come off the fill fitting and down about 2 feet, then straight for 4 feet and into a 45degree fitting on the front of the tank. The vent comes in, up about 8 inches(to form a P trap) the down the 2 feet and 4 straight onto the vent fitting on the tank.
I am at a loss. Please help me out here.
I will update with photos shortly.
Thanks
Scott
I have 18' CC with a below deck fuel tank. When I rebuilt the boat and floor 2 years ago, I installed a recycled alum. gas tank below deck. After cleaning and coating the outside of the tank with coal-tar epoxy, All of the hose were installed new, with alcohol resistant marine grade fuel hoses. The fill and vent fittings come off the front of the tank and I installed a new pick-up in the rear of the tank. The hoses are about 5' long and run under the front deck and through a storage compartment under the front of the boat, then up to a fill fitting and a vent thru hull fitting with a screen. After the boat redo 2 years ago, the boat has worked great. The fuel tank has operated properly and the vent and fill worked as designed. My boat has been sitting for 8 months and I am now trying to get her back up and running.
The PROBLEM: now when I attempt to fill the tank with fuel, it acts as though the vent is inoperable. It takes a little fuel, then fills up the fill hose and out the top, the tank is a 24gal tank and it only has about 6 gals in it. Also, when I unscrew the fill cap, there is a release of pressurized fuel vapor. If I leave the fill cap on as it should, instead of vapor escaping from the vent as the fuel boils off and expands, liquid fuel is coming out of the vent fitting. I attempted to blow air into the fill by mouth, and there is a moderate amount of resistance/pressure in the tank. The trailer jack is up high so the boat is pitched nose up (to prevent the fuel from resting on the fill and vent openings). Because of the negative pressure created when running with the cap on and the vent not working properly, the motor doesn't run properly on the on-board tank. The motor runs great on a portable tank.
What I have done to problem shoot:
1) I took the vent hose off the tank and off the thru hull fitting. I removed the fitting and cleaned it up. (it was pretty clean when removed) I blew air through the hose and verified that it is not clogged.
2) I then placed a very small compressor on the vent and blew air in. When I blew air into the vent on the tank, air came out of the fill opening.
3) I then placed a 1 foot piece of vent hose on the vent opening. I then took a shop vac/blower and blew air into the fill opening. Liquid fuel came out of the vent hose and filled the catch can that I placed the hose into.
4) I also made sure that there was no kinks in the fuel lines. The fill hose come off the fill fitting and down about 2 feet, then straight for 4 feet and into a 45degree fitting on the front of the tank. The vent comes in, up about 8 inches(to form a P trap) the down the 2 feet and 4 straight onto the vent fitting on the tank.
I am at a loss. Please help me out here.
I will update with photos shortly.
Thanks
Scott
