Internal fuel tank problem?

[merryacht]

I have a 1988 Lund 5.5 Tyee. I love it! it is powered by a 1987 Suzuki dt 85.

Here is my problem.

It seems that as the fuel tank empties, the ball won't pump up. I have rebuilt the carbs, changed the fuel filter, rebuilt the fuel pump, tightened all the fittings, replaced the suziki connecters, checked the lines for pinholes. NOTHING helps me as the tank empties to keep the bulb hard. This thing runs great at faster speeds, but trying to idle at the dock or slow troll simply empties the bulb, which won't then pump up.
I have removed the fuel line from the motor via the quick connect and attempted to pump up the ball that way. It only pumps up hard when the tank is full. When it is down to 3/4 the ball won't pump up.

Question?
Has anyone ever even heard of this? Could it be an internal tank problem with a pinhole or something in the pick-up pipe within the tank? Also, at times my fuel gage sticks on full, even after it has read 1/2 full.
Are these 2 seperate problems?

i am going to try an external tank to see if the engine will idle and troll, and will keep you updated.....

Help anyone???

 

[P.I.K.E.]

Re: Internal fuel tank problem?

Did you replace the check valve in the fuel line?

 

[merryacht]

Re: Internal fuel tank problem?

If you mean the check valve in the bulb or ball used to pump up the line, then yes, that is new as of this year. Is their another in the tank?
Thanks for the reply.

 

[Silvertip]

Re: Internal fuel tank problem?

You may have other issues. Primer bulbs do not stay firm after the motor starts. Fuel is being sucked through the bulb so there is no pressure in it. In fact it would have a slight vacuum. Some primer bulbs will also not firm up unless they are held somewhere between horizontal and full vertical. If it is held with the engine side pointing down it may not prime. You don't say the engine actually dies because of lack of fuel so that leaves the problem open to lots of possibilities. None of the stuff you mentioned will prevent a primer bulb from firming up. It may not hold pressure with the engine off but even that's not a problem. Leaky fuel fittings however will cause the engine to suffer lack of fuel issues but it won't be because of the bulb (unless the bulb itself is obstructed in which case it will be sucked flat.)