94 gtx vent line check valve

[bobw2961]

I have a 94 gtx that runs great on the lake for about 15 to 20 mins. Then starts bogging down like its not getting fuel. It gets worse fast to the point that it will not run. I have already cleaned tank, replaced fuel lines, and cleaned carbs and fuel selector. I am sure that these are not the issue. After the ski sits overnight, it starts and runs fine again the next day for 20 mins. Other threads in this forum have talked about plugged vent lines causing fuel delivery issues. My ski has two vents. One goes to the side of the hull and has a normal check valve. The other goes to a fitting in front of the seat and it seams to be a one way relief. There seems to be several opinions as to which way these valves should be installed. From what I have read, the 1.5psi relief is to keep the tank from pressurising so it lets air out after 1.5psi, and does not let air in. The other seems to be to keep the tank from forming a vacuum. It lets air in, but does not let air or fuel out. Once and for all, can someone tell me if this is correct? If so, what keeps water from entering the normal check valve?

 

[bobw2961]

I found in the service manual that the 1.5 psi check should let air out but not let air or water in. I checked mine and it was backwards. I turned it around. I found that the other check was plugged. I cleared it out and it seems ok. It allows air one way but not the other. Took it out to the lake and never had any more problems. Apparently the tank was pressurizing and was not able to vent. This messed with the fuel pump. Everything seems fine now.