I have suction problems when I get below half tank, the pump cant suck the fuel out of the tank?? I have rebuilt the pump same problem changed the filter, new connection to the motor, still nothing. It will run fine on an external tank. My question is if I can run an external pump inline to solve this problem.
Fix the problem, not the symptoms. Is there a bad anti-siphon valve in the tank? How about a filter that may be restricted? How about the pick-up tube in the tank? Does it go clear down almost to the bottom? How about, does it have a hole in it half way down? There has to be something wrong if it will run OK on a portable.
Well I looked at all of that and there is no hole in the pick up tube and yes it dose go to the bottom and the sending unit works. I also have a clear filter and I can see that there is no air in the system. so what is next??
Me thinks your best bet would be to solve the problem that you have rather than bypassing it. From your description you have a problem with the pick-up in the tank and/or the tank is not properly vented giving you a vapor lock.
You could use an external pump but they are electric and quite expensive. My boat came equiped with one. When it went south the replacement was over $200.00.
Your anti syphon valve is located at the tank, but I understand your thinking by saying your bulb. It is usually located where the fuel line goes from horizontal to vertical. I would replace it first.
The only things that I can think of that would cause that problem are the ones listed by FR, might want to go over them again. How do you know the anti syphon valve was ok by the way? I think if it is vented properly, the filter is not clogged , the pick up is clear and the hose is laying on the bottom of the tank, it would point to the anti syphon unless anyone has any other ideas.
well when I had that out of the fuel tank I was abel to blow air one way but not the other so I would assume that it is working. The manual only shows an external tank being used? I am thinking tha an 1988 pump will fix the problem since the engine is an 1986.. so what is next??
Let's go back to the beginning. You said that it is OK until the tank is half empty then it runs out of gas. That should be a clue. There is something wrong with the pick-up tube in the tank, or the tank is not vented.
Is this a built-in tank or a remote 6 gal tank? Are you sure the gauge on the tank is ok? Check the seal at the top of the fuel pickup where the pickup meets the head. If it's loose, it will not suck fuel properly. Usually the anit-siphons work or they don't. Unusual to have them only work on a full tank. F_R has the right comments. Run it on another tank and see what happens.
The remote tank is a 6 gaallon. I just replaced the sending unit and it has new seals and is in good working order. I will pull the pick up tube out again and look at it but I know that it is working fine I am really confused
I've had lots of problems with brand-new primer bulbs. Quality control seems to be an issue. I've had to buy 2 or 3 to find one that actually works correctly.
See if you can put a piece of clear hose in line immediately before the fuel pump.
While running and as it is failing can you see any 'bubbles' in the clear line?
Bubbles indicate air is leaking into the fuel line somewhere, a ppin hole before the primer bulb, poor hose to barbed fitting, something lets air get into the line just as if the tank has run out of fuel.
How do you know you have 1/2 tank, did you take off the sender and look/measure with a stick?