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My M37 has always started right up I just returned from vacation and it has only been about 10 days since running the truck and now it will not start. I choke it and it runs for a couple of seconds and dies. The gas is fresh about 2 weeks old where do I start the process of elimination?

is the fp workin? is the carb clogged? does the float and needle move freely? do you have a fuel filter on it? is the power lead to the dist good? just things we found to be wrong each time ours would not run

I have what I believe is an original fuel pump on my 52 M37 it is located on the bottom left front of the engine as you face the truck. Next to the pump is a glass bulb fuel filter. I pulled a line after the pump and before the carb and turned the eingine over for about 10 seconds no fuel pumped out. I also gave a quick shot of starting fluid into the air intake and the engine fired and then stalled. I am not machanical at all does this sound like a bad fuel pump? Is it unusual for one to quit while the truck is not running? What is the easiest replacement if I need a new pump? Thanks

I went ahead and squirted some gas in tot he carb it started right up and ran for a minute or two then stalled. Bad fuel pump right? Can a fuel pump lose its prime? Anythign else I am not thinking of? Thanks

Disconnect fuel line from the carb again and then use the hand primer lever on the pump. Note you have to pull it through a full stroke. it moves easy at first but then you will feel significant resistance.. that is the phase of real pumping action) pull it as far as you can. it may take many strokes. if you get nothing after 50-70 stokes either your pump is toast or your fuel line is blocked...you did check that??

D - we had the same problem, fuel at the pump, nothing at the carb. We pulled the pump off and had oil dripping out the cam end...hole in the diaphram. Sent to Then&Now, Tony rebuilt it in 6 days, $95. Also, you pump may not have the little primer handle as they tend to snap off.

Where is the hand primer located? Sorry for the dumb question what does it look like?

dman wrote:Where is the hand primer located? Sorry for the dumb question what does it look like?

If your pump has the glass bowl, that is a non-original pump for the M37 engine. This type pump has no primer lever. As you have stated, you have disconnected the fuel line between the pump & the carb bowl & cranked the engine with no evidence of fuel delivery. This certainly indicates a bad pump, IF YOU ARE SURE THE LINE IS OPEN FROM THE TANK TO PUMP, you need to check the pick up tube in the tank also. The type of pump you have is ok, but my preference is the original type. You can get a replacement like the one you have at NAPA, so that makes it simple if you want to stay with that type.

Charles any idea what the NAPA part number might be? I got these from a replacement parts list on the web
NAPA 2766 ($62.00)
NAPA M2091 (1950 & After)

dman,

The pumps are easy to differentiate if you know what the original looks like. Here are two pictures. The first is the military pump (fuel pump on top and vacuum pump on bottom) with the priming lever easily identifiable. The second pump is the common civilian pump used. I'm using the civilian pump until I can rebuild the military pump.

And yes, these pumps can go bad just sitting there. Many times the rubber used in the diaghram doesn't like stuff in modern day gasoline so it has a chance to deteriorate.







Corey

I bought a exact replacement of what I had from NAPA M2091 . Lst question I promise are the mechanical pumps self priming? So basically I put it in and crank it over and fuel should flow? Thanks

Both types of mechanical pumps I have used on my M-37 were self priming. Now, it's probably better on your batteries to try to get the fuel up to the pump manually first, but it should work either way. I use a dangerous process of 'priming' my truck, but I'd not recommend it.

Corey

Priming manually isn't necessary.

great information and the pictures made it clear what I found on the splash shield was the broken off handle. Now we need to know who sells a replacement handle and how hard is it to change out. Can the pump stay on or does it have to disassembled. Thanks and sorry for jumping in

the pump has to be removed to replace the handle, in fact it requires an almost total dimantle because the handle is peened on to the shaft that primes the pump and there's a small linkage inside under the fuel diaphragm. might be a good time to consider a rebuild....