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Fuel Pump Problem

C

colriverrat

Contributing Member
"I just installed new rings an

"I just installed new rings and pistons in my 1980 DT65. It is a two cylinder motor. I replaced the fuel pump diaphragm set, but still low fuel flow. I have to keep pumping the primer ball every 15-20 seconds to keep the motor running.

Are there any other serviceable parts in the fuel pump, or do I have to replace it? A new one at Browns Point is $115 OUCH. Is there anything else I should check before replacing the pump?? I have a brand new fuel tank, and primer ball. The tank vent is open.

Is it possible I put the pump together backwards? Should I try flipping the pump over?"
 
The pump has chk valves in it.

The pump has chk valves in it. Put a vacumn gauge on it and see what it pulls while cranking.
 
There are usually marks on the

There are usually marks on the case. make sure you lined them back up. If you didn't have marks and you didn't mark it before you took it apart you will have to figure it out. Not that hard. some of those pumps had a o-ring or gasket that would seal the pulse hole make sure it's there.
 
"Thanks Robert, I did mark the

"Thanks Robert, I did mark the pump with white paint after I took it off the motor. I lined up the marks when I put it back together. The pump has 2 fittings almost 180* from each other, is there an in and out?? I might have it upside down. I just figured the lettering on the pump face so you could read it.

The O rings are new, came with the repair kit."
 
Some of those Mikuni pumps had

Some of those Mikuni pumps had a arrow on the pump one pointing in and one pointing out. There is a inlet and oulet. You could Vacumn test it real quick. I wouldn't rely on being able to read it. You could also pull the pump off real quick and you should be able to blow through one end and not the other. I doubt you have it on wrong though you said you can pump the primer bulb and keep it running. I think you need to look at those chk valves again.
 
They don't sell the chk va

They don't sell the chk valves you would have to buy a new pump.

That should work fine 3-5 lbs of working pressure with a shut off and good flow 20-30 gph. You could wire that into your key switch turn the key on and your good to go. I'm suprised none of the manufactures offer any kits to convert over.
 
"Thanks again Robert. Looks li

"Thanks again Robert. Looks like I'll go with the electric. I was able to blow through both sides of the pump. I took the pump apart again, the check valves are very thin plastic, both have a slight warp."
 
"One more ? Will I need to cov

"One more ? Will I need to cover the pulse hole on the block? I plan to just leave the factory pump on it, I don't want a possible air leak down the road."
 
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