The Stovebolt Site Forums The Shop Area Engine Shop Fuel Pump Recommendations

I seem to be having a fuel flow issue and in the interest of baselining I need to replace my fuel pump.

- Stock 235

Any recommendations? Any to be avoided?

Thanks!

Have your original pump rebuilt or buy a rebuild kit. All new pumps come from China and the possibility that it will not work right out of the box is high. If it does work, you'll be lucky to get 1000 miles out of it.

See this thread where I went through this last summer.

https://www.stovebolt.com/ubbthread...umps-and-other-nonsense.html#Post1468947

Contact Then&Now Automotive for a kit or better yet, in my opinion, send your pump to them for rebuilding.

I'm not sure what you mean by the word "baselining". If that means throwing a fuel pump at your fuel flow issue and hope that it permanently solves your problem, there are some things which you can do first.
1. Test your fuel pump delivery at the fuel line at the carburetor.
2. Check for free flow of fuel coming out of the tank.

What I mean by "baselining" is replacing all consumable parts (normal wear and tear), good or bad, just so I know what their condition is.
Removing the variables and setting a baseline going forward, so I know what I am working with.

I have installed new fuel filters and fuel lines, flow is good at the one just before the carb at idle, but it you take it up to 50 it goes into a fuel starvation situation. Checked the filter after stalling out and you can see it not getting fuel. I think the fuel pump diaphragm is disintegrating.

So, I was planning on replacing the fuel pump as part of my starting baseline, good or bad.

Hope that makes sense!

I picked up a Airtex pump.

Airtex, I dont think that is where you want to be. They are not great in terms of quality. What a stock motor and carb need is about 4 -5 pounds of fuel pressure max. Every Airtec I have messed with is 6-8. Its too much and plays havic with the carb. So you are not going to get the base line you are seeking, unless you are lucky. If you take the AC style fuel pump you have, and get it to a real builder, like Then and Now, you have a chance because they will confirm the output pressure. Bite the bullet and get something decent for your motor.

Kilroy,
Can you explain as clearly as you can what you are observing at 50 MPH? Stumbling? Engine stops running? Won't start after it stalls? Etc?
You may not have a fuel pump problem at all. It could be ignition system related, or some junk floating around in the gas tank which settles on the pipe coming out of the bottom of the tank from time to time, such as when at full throttle when more fuel is heading out of the bottom of the tank, pulling the junk to the end of that tiny pipe.
That is why I hesitate throwing parts at problems (not saying that I haven't from time to time).
Lets say that you put that Airtex fuel pump on and the pressure is way to high and blows the needle off the seat in the bowl of the carburetor and causes a flooding condition, but the problem was electrical to begin with. Now you have twice as many problems as you had before.
I'd like to hear what you have to say about what you are observing when it acts up at 50 MPH.

It seems so run fine unless I accelerate hard, then it dies.
Once it starts again it takes it a little while to get back to normal.
When I stopped and checked it last time, the fuel filter by the carb was almost empty.
I have changed the plugs, cap, rotor and condenser and both fuel filters. Air Filter is a permanent K&N type,

I'll be putting it on tomorrow - I'll post the results!

Fuel filters are perhaps better placed between tank and fuel pump because it doesn’t take much contamination to keep the check valves in the pump from closing sufficiently to get pump action
Maybe the problem is just a tiny bit of crud in the pump keeping one of the valves from seating which would severely limit fuel delivery

If it was me based on what you describe
I would remove and clean the pump and reinstall
And if that fixes the problem
Move your filter to front side of pump
The fuel pump is nearly as delicate as the carburetor to contamination causing issues.
-s

Set the float level correctly- - - - -you're emptying the float bowl at full throttle and creating a surge. If the fuel pump will flow a pint of gas in 30 seconds at idle speed you have plenty of capacity to support wide open throttle for miles if the float level is OK.

A clogged exhaust system will also cause the symptoms you're experiencing. Take the muffler off and do a test drive.
Jerry

Next time it dies on you, crawl in the engine bay so that you can see down the throat of the carburetor and goose the throttle lever on the side of the carburetor to see if you get a squirt of gas from the accelerator pump. This will verify if there is gas in the bowl or not.
If there is no gas squirt, follow Hotrod Lincoln's advice.

If you decide to buy instead of rebuild Carter fuel pumps are still made in the US. they are made in Logansport, IN. I put a Chinese made fuel pump on my 47 and after less than 20 starts of the engine the pin of the pump arm popped out and went into the oil pan. I purchase a Carter and it had an epoxy plug on each end of the pin to prevent it from coming out, a common problem. eBay - autopartsgeek2 $61.84

Was that a recent purchase? I don’t believe ALL carter pumps are made in USA nowadays. But I can’t speak specifically M751.

I bought it about 2 months ago. I could have been miss-lead. I checked mine and it does not have a location stamp on it like the attached picture. Mine is a model M2090. I know some stuff has moved to Mexico, which is better than China. I checked several suppliers just now. Most don't list country of origin. A couple eBay sellers listed it as Country/Region of Manufacture:
United States

I have a filter before the fuel pump and one after it.

Replaced the pump yesterday, ran better at 50 at first than it died again.

I'm thinking is the carb that needs attention next.

Disconnect the fuel line at the carburetor and crank the engine. Is fuel reaching the carburetor?

If not, the fuel pump is bad (or there is a blockage in the tank or fuel line). Don't assume it's good because it's new.

If fuel is reaching the carburetor, then look more closely at the carb and ignition components.

Did the truck restart after the conkout? How long did it have to sit before it would restart?

I have a glass filter just be for the carb and you can see the gas flowing and it's reaching the carb.

It takes a bit of cranking before it will start again.

Look down inside the carburetor with the engine off and goose the throttle by hand.

Can you see a squirt of fuel in the carb throat with each pull of the throttle? If not, your accelerator pump is not working and carb rebuild is in order.

When the engine conks out, is the fuel filter bowl at the carb full of fuel?