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uneven fuel tanks

7K views 27 replies 14 participants last post by  sneakyneon 
#1 ·
Hello all, I have a 19ft jet boat with saddle tanks that hold approx. 12-13 gallons each side. The issue I am having currently is that one side is pretty much completly draining, without the other side moving at all. I never had this issue before and I have owned the boat for about 10 yrs. or so. The only thing that has changed recently is my motor combination, but the fuel system has stayed the same, lines, pump, ect. I checked the tank and nothing is clogging the pickup, so I know that's not the issue. I was wondering if something weird like an air/ vapor lock could be happening on that side? At this point I'm open to any and all suggestions. Thanks.
 
#5 ·
the system is plumbed as follows: not 100% sure but if I remember correctly I have a -10 line coming from each tank ( and yes they are equidistant or at least very close to it) into a t fitting. That feeds a bg 5000 fuel filter, the filter is plumbed directly into my fuel pump and from the pump is a another -10 or -12 but I think it's -10 to the regulator, (it's a dead head). I checked the non drawing tank with a bore scope, nothing blocking the pickup, I put a coat hanger down it and visually seen it go into the tank. Thanks for the suggestions, keep them coming! as I am at a loss...
 
#8 ·
Check your'e pickups I have seen them suck air after time and you end up with the situation you have. Easy way to check is hook up one tank at time thru an electric pump with clear hose and watch for bubbles. If no bubbles, go with what futs said and check the internals of the rest of fuel lines. If you cant come up with a cheap electric pump and clear line the disconnect one tank at a time and pump into a clear container again watching for bubbles. Make sure to plug the other tank for the test. M
 
#10 ·
I agree with the one tank at a time theory to diagnose the problem. Simply unhook the good tank and cap off the line. If it is pulling air you should be able to find it. If it is sucking the hose collapsed you should be able to find that as well. More than likely the filter is partially clogged and it draws from the side of least resistance. You can always blow air back through the line to the tank not drawing and ensure it cleared out that way. Or cap of the line at the tank and put air into the line from the pump end and make sure there are no leaks.
 
#13 ·
We lost a race a couple years ago when the thing ran out of gas, with one tank almost complete full. Had never happened before. Two tanks did equalize the the fuels after 5-6 hrs. Exactly the same in each tank, on e empty, on full. Turned out to be the vent line collapsed and kinked completely shut.

If its not the supply lines, check the vents. If it vents thru the caps, remove the full tank's cap and see if the tanks equalize sitting on the trailer.



 
#19 ·
I know this is an older thread but this is the same issues I'm having with mine, My question is, Would popping the cap open vent the tank? I have a manual slector ball valve, I can swith to the bad tank and run the boat till it starts to spudder, Ive popped the cap but its still dies out, Would this be a clear way to ruel out the vent?
 
#20 ·
Do you have return lines form the motor to the tanks? If so, make sure that fuel can return to each tank, if it's only returning to one tank then you are going to fill that tank up while the other gets sucked dry...could be one tank "siphoning" fuel from the other tank.
 
#23 ·
I too was Mardon this weekend!

So this leaves me in a pickel, the tanks are aluminum but are glassed in to the boat. I could cut it out I guess but maybe I should drill and tap that tank for a pipe fitting in the bottom rear of the tank? Maybe not the best Idea but if wont work I guess I'm still down to one tank...
 
#25 ·
X2...I have to pull a side panel and unscrew those pickup elbows off the tank every other trip to pick crap out that gets stuck in the ball valve, usually aluminum shavings...but i guess they are necessary to have...anti-drain back?
 
#28 ·
So I drilled and tapped a fitting in the bottom of the tank, took it out and still ran dry with 1/2 tank of gas, I had a pretty big loop of fuel line to the T valve, I moved the valve lower than the tank and shortened the line. I also used the old pick up spot for a vent, just a barbed fitting and some hose hooked to a coiled piece of aliminum tube. Time to go back out and see what happens
 
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