Venting problem??

[Wally World]

Ok, I have a very confusing scenario brewing.

I just bought a 2002 Express 330 this season and it is the first time I have had a boat with two gas tanks.
First question is when filling up which gas cap is the main and which is the auxiliary? (front or back) When I fill up the front cap it will constantly quit like it is full but I know it is not, so I thought that I had a venting problem. But when I fill up the back cap it takes it no problem. From what I can see there is only 1 vent out the starboard side which would lead me to believe that the two vents connect via a T somewhere?

Next problem is that when I switch my fuel switch to read the main tank it reads a half a tank which I believe to be correct. But the Auxilary reads as full. This I do not believe to be true since when I bought the boat up from Alabama it had allot of condensation in the tanks and I had them drained completely and never topped them off. Just added enough fuel per trip to keep changing the fuel over faster. Sender problem?

This is part one of a puzzle I have been working on. I would like to get some feedback from other 330 owners so I can proceed to part two of this puzzle.

 

[ElyseM]

first, the vents are inside of the fill caps. if you look closely, you should see the vent slit at the bottom of the cap threads. wnen you fuel up, you should hear an air gushing noise coming out of the fill. if not, the vent is plugged. also, if you are using a fill nozzle that completely covers the the fill, it is probably blocking the venting. the vent on the side of the hull is for the head waste tank.

check your manual to see which fill goes to which tank. if you don't have one, you can pull it down from the GW site.

the tank level sender may be bad. check the connections at the switch and the ground and sender connections on top of the tanks first. they should be clean and tight. if so, time for a new sender.

good luck, ron

ps: all of this assumes oem and not a diy "looks good enough" repair.

 

[DennisG01]

In addition to the above, follow the vent line back to each tank and look for low spots or dips in the hose where fluid can accumulate.

PS: You might actually end up with more water in your tank by not keeping them full. While ethanol gas (if that's what you are using) can attract moisture out of the air, another main problem is when tanks are only partially full as it allows the tank (aluminum, not so much plastic) to form condensation on the interior walls.

Forgot to mention - when you're at the sender, the key on, remove the center wire (pink, I think?) and short it to ground. You should see your gauge go from empty to full. If that happens then, as mentioned above, check out your sender. It could be stuck, or it could be bad (possibly from water). Pull it out and, with the wires attached, move the float arm and observe the gauge. Also try pushing a little harder on the metal contact arm. Sometimes just cleaning it helps, or bending the arm so it makes better contact.

 

[jip40]

On my 2002 330, the aft gas cap is for the main tank. I would assume that is the same for yours.

 

[Wally World]

Thank you guys for your input already learned a couple more things today then I knew yesterday. I will keep trouble shooting. Thank you. Any other input is appreciated.