What's the difference between these two fuel pumps?
 

What is the difference between the fuel pump for my 47 and the one for a 51 Custom? I think I've got a bad one on the 51 and have a spare for the 47 I want to try on it.

Re: What's the difference between these two fuel pumps?
 

Not positive, but I think the 51 would have a dual pump, to serve the windshield wipers. Wouldn't be a problem unless you wait till winter to sell it!

Re: What's the difference between these two fuel pumps?
 

The early pump won't work.
The push rod cup is smaller in diameter on the early pump.
Also on the '47 pump the mounting flange is about a 1/4" shorter and would not seal.

Re: What's the difference between these two fuel pumps?
 

As 42merc mentioned, there are several differences, the mounting flange being the most noticeable. The dual action pumps were OEM optional accessories, in addition to fuel delivery/pressure, they provided constant vacuum to the windshield wipers.

Re: What's the difference between these two fuel pumps?
 

Thanks guys. You saved me one more futile attempt to fix this annoying fuel delivery problem. Guess I'll spring for a new pump and hope that is the last and finally successful attempt.:cool:

Re: What's the difference between these two fuel pumps?
 

Have Charlie ny rebuild it. It will be better than new.

Re: What's the difference between these two fuel pumps?
 

Or ken ct.
Very fast turn around
Randy

Re: What's the difference between these two fuel pumps?
 

I have dealt with Charlie NY and Ken Ct and in regard to my refurbished units I was completely satisfied with both, and if you are using ethanol gas they can provide/install the proper parts. Could be taking a chance with a "new" unit.

Re: What's the difference between these two fuel pumps?
 

Are not pumps very easy to rebuild? I rebuilt a couple of extra ones that I had for spares, seems pretty straight forward with a good kit.

Re: What's the difference between these two fuel pumps?
 

Why Do you keep saying the bad pump /you are getting bubbles in the fuel filter & that is before the pump / Should be a problem down stream of the pump >>

Re: What's the difference between these two fuel pumps?
 

I get bubbles in the bowl of my pump too, what causes that?
Ian

Re: What's the difference between these two fuel pumps?
 

I put a clear tube in place of my flex hose so that I could see better what was going on. There were some very small bubbles coming up through the fuel line but the bigger problem was with the fuel pump. The one way valve in the pump is not working properly. When the pump gives a suck the gas moves up the tube some but then when the suck is over it moves back down the tube. The problem gets worse as things heat up to the point that eventually the gas is making no progress at all in the tube and just moving up and down with each pump instead of advancing. And, when the engine is shut off the fuel quickly drains back down the tube when it should stay in there and not drain down at all. That was my very first hunch when I started with this problem but wanted to eliminate all other possible causes before springing for a new pump. I am hoping that with a new pump the air bubbles won't be a problem because I have no idea how they get in there.

Re: What's the difference between these two fuel pumps?
 

Can you show picture of where clear hose is located ?

Re: What's the difference between these two fuel pumps?
 

Here's the video: http://youtu.be/g5EMoSqB_I4

Re: What's the difference between these two fuel pumps?
 

I May be slow but how can it be the pump if the bubbles are moving up the hose towards the filter & pump not away from the pump / That clear hose is cheap / make a long one in to a gas can and see .

Re: What's the difference between these two fuel pumps?
 

This video does not show the problem with the pump I described earlier, just the air bubbles. They are two separate problems. Since I have no idea where the air bubbles are coming from and have no idea what to do about them I'm hoping that by fixing the problem with the pump the air bubbles won't be a problem.

Good idea about the tubing to a gas can. I may try that before I buy a new pump and see if that fixes the pump problem. Unfortunately, I'll still have the bubble problem that I have no idea what to do with.

Re: What's the difference between these two fuel pumps?
 

Try the longer hose to gas can You may see no bubbles / I think you have now is the bubbles come up hose and collect in fuel bowl and then the pump skips a beat and engine quits.

Re: What's the difference between these two fuel pumps?
 

You may well be correct. It makes sense. But, I hope you're not. Otherwise I'm dead in the water because I don't know what to do about the bubbles.:(

Re: What's the difference between these two fuel pumps?
 

Can you remove the gas line at the tank ? If so plug it at tank end / take your little air compressor and make a tight connection at engine compartment end / plug in compressor and look for leaks >>

Re: What's the difference between these two fuel pumps?
 

A possibility is an internal crack or rust thru of the pickup tube in the tank.
If you haven't done it already try filling the tank full to see if the situation goes away until the fuel level gets below the defect.