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AQ120b fuel delivery from tank issue

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YellowYaro

Member
Struggling to get gas from gas tank to engine. I.e. Won't suck gas from tank at all.

No problem running from remote gas tank with only difference in setup is no pick-up tube or AS (anti-siphon) and remote tank being on deck. As opposed to aluminum tank under deck.

Current setup:
Pick-up tube (original?) filter gone, tube clear, not cracked to ***** eye
Anti-siphon (original?) clean/clear, seemingly functional, tryed operating it with it forced open resulted no change.
Inline Filter new
Water-Fuel Seperator new
Fuel Pump mechanical (old) works fine on remote tank
Hardline to Sidedraft carb clean clear works fine

Gas tank vent clean
Gas tank cleaned

To get it to run I have been using a fuel hose to remote tank.
I took the same hose and bypassed the pickup tube and AS directly into gas tank RESULTS= still won't suck up gas.
Same length tube. Didn't change anything else in the system.
Water-separator and previous fuel filter still primed.

Possible solutions:
fuel pump weak needs replacing, but runs fine on remote even up to speed.
fuel lines not primed to perfection. Air not allowing gas to enter lines?
Cracked pickup tube, but when bypassed still doesn't take gas from tank
broken AS, still when bypassed or forced open no changed
gas tank still has debri in it clogging line or pickup tube instantly (I doubt it)
air leak in system... Can't find one or hear one. Not leaking any fuel either.
Gas tank elevation compared to remote tank on deck. The remote tank being above filter and water fuel separator makes it easy for gas to sucked by fuel pump. As opposed to permanent tank in boat, filter and water separator almost level with top of gas tank. Easier to travel downhill then uphill. If the fuel pump is adequate it should be able to suck up no problem.

More options??

what should fuel pressure be at?
 
Clearly you problem is in the tank, I said AS valve is bad, it could be remove if the rest of the system is above the tank, air leak, a vacuum and pressure test is in order, could be a pinhole somewhere in the delivery system, the tank and lines should be able to hold pressure or vacuum for at list 5 minutes.
 
How old are the fuel lines to the tank? If pre ethanol, then you should be aware that ethanol dissolves/softens the linings of some fuel lines.
 
Struggling to get gas from gas tank to engine. I.e. Won't suck gas from tank at all.

No problem running from remote gas tank
Click to expand...


Given that your Engine operates correctly on a remote fuel tank:

Pull the fuel tank "dip tube" and examine the screen. Remove the screen if need be.

Replace Anti-Siphon Valve. Anti-Siphon Valve will be at the top of the dip tube just after the 90* fitting.

Remove the existing fuel filter "base" and look at the inlet and outlet ports.

Replace all fuel lines with A1-15 USCG approved gasoline fuel line.

Although likely NOT the problem, make certain that the fuel tank vent line is clear, and that it makes a "high loop" prior to it's connection to the over-board vent line fitting.


.
 
Last edited:
gotsea said:
Clearly you problem is in the tank, I said AS valve is bad, it could be remove if the rest of the system is above the tank, air leak, a vacuum and pressure test is in order, could be a pinhole somewhere in the delivery system, the tank and lines should be able to hold pressure or vacuum for at list 5 minutes.
Click to expand...

It's not clear to me. I bypassed the pickup tube and AS. Took fuel hose directly from remote tank to permanent tank and it wouldn't pull up any gas. Why do you think that is? Do you know what the pressure should be # wise?
 
sandkicker said:
How old are the fuel lines to the tank? If pre ethanol, then you should be aware that ethanol dissolves/softens the linings of some fuel lines.
Click to expand...

most the fuel lines are new. There is one section of hose about 1ft long that is older but it works just fine with a remote tank. I will keep that in mind thank you.
 
RicardoMarine said:


Given that your Engine operates correctly on a remote fuel tank:

Pull the fuel tank "dip tube" and examine the screen. Remove the screen if need be.

Replace Anti-Siphon Valve. Anti-Siphon Valve will be at the top of the dip tube just after the 90* fitting.

Remove the existing fuel filter "base" and look at the inlet and outlet ports.

Replace all fuel lines with A1-15 USCG approved gasoline fuel line.

Although likely NOT the problem, make certain that the fuel tank vent line is clear, and that it makes a "high loop" prior to it's connection to the over-board vent line fitting.


.
Click to expand...

Mr. Ricardo,
thanks again for all your help and others to initially get my boat running with my last issue.

I have already pulled the "dip tube" and the screen is non existent. The tube looks clear and functional

same with AS valve, pulled it, seems functional, I also bypassed it
by inserting the same fuel line I use to run from the remote tank, I transferred the same hose to the permanent tank and it won't suck gas...


The filter is brand new only been on for 2 gallons of fresh fuel from remote tank. I'll still remove and check. But once again it still works fine on remote tank.

Most fuel lines are new but not all so that might be a possibility but still the same question... Why does it work on remote tank not permanent?

i did just double check that the vent hose was clear before I posted this question. And it does have a loop at the top.
 
Read post #4 buy a pump and diagnose from there. Checking fuel pressure is a waste of time, if you dont know how old the pump is make it a known!
 
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