Starting an M37

[slk]

Hey guys do you have any tricks to make these start easier. Mine usually sits for long periods of time before I use it, and I know that is not good for it but it is what it is. It was parked all winter long in my barn (6 months) without being run. I tried and tried to get it started, but no go. A mechanic friend of mine suggested to pour a little gas down the carb. I was doubtful that would work with a side draft carb but to my surprise it kicked right off and ran great. He said on his plane which does not have an accelerator pump either he has a little squeeze bulb that shoots a little gat to the carb for that reason. Anyone have any suggestions that have worked, or a procedure that I should be following for these vehicle's??
Thanks
Steve

[John Mc]

NOTE: I am far from an engine guru, so take this with a grain of salt. Perhaps someone more knowledgeable can confirm or correct this

Does it start easily if you run it and then start it up later that day or the next day? If so, there's a chance your carb bowl is slowly running dry if the truck sits for an extended time. I think I had that issue myself. Truck would start easily if it had only sat for a few days, but was tough to start if it sat for a few weeks. Squirting a little fuel or

I had the the truck in a friends shop for some other work and putting in a rebuilt engine. While it was there, we had the carb rebuilt. I asked him to take a look at the fuel pump. As it turns out, that was due for a rebuild as well. Rather than rebuilding, I switched to an electric pump (which should let me prime the system by letting the pump run for a few seconds before starting, if I run into that problem again).

Between both of those items, I'm hoping that I no longer have to resort to having my son squirt a little starting fluid (or my chainsaw gas mix) into the carb intake as I crank it over, as I did in the past after the truck had sat for a few weeks.

[Cal_Gary]

Some M37s had a fuel primer pump on the dash.
Every M37 is a bit different to start based on a number of things: compression, starter RPMs, degree of timing, choke position, etc.
Mine takes a full choke when starting "cold" then no choke when warm. Doesn't matter how long it's been sitting. I will add that the high-rev starter I added last Spring helps it fire up quicker.

Like they always told us in the Army, "You gotta know your equipment!"
Gary

[slk]

I agree there. Every piece of equipment seams to start differently. All of them have their quirks. I am interested in the comment about a primer bulb on the dash. Where would it have been? Was it standard equipment or an add on?

If the truck only sits for a few days it will start right up. The starter is slow in them, but does ok if it does not sit for weeks.

Steve

[greeno]

The Canadian version of the M37 had the primer bulb in the dash. I believe it's easy to retrofit into any M37. John @ Midwest Military has the entire kit.

[John Mc]

The Canadian version of the M37 had the primer bulb in the dash. I believe it's easy to retrofit into any M37. John @ Midwest Military has the entire kit.

I wonder if that works like the hand primer in some piston powered aircraft (the ones that have a carb, rather than fuel injection). You pull the plunger on the dash out, and the reservoir fills up. Push the plunger, and it squirts fuel into either the intake manifold or directly into one or more cylinders (depending on the engine model). We were always warned to make sure this was kept in tip-top shape, since it was drawing fuel past the firewall and into the cabin. A leak in that system put fuel where you really don't want it. It was very effective in getting the engine started.

[Murf]

Yes, that's how it works. Small copper tubing carries the gas. If you look at your intake manifold the pipe plugs on the top are replaced by the brass nipples in the kit. Warning! the brass and copper is very soft. Overtightening the compression nut will snap it right off the nipple.

[slk]

Does anyone have any pictures of the entire pump and lines to where they go. Where it is mounted on the dash, and how it connects to the carb or intake??

Thanks
Steve

[Murf]

You can find them cheaper but here it is. (No affiliation just saw it was complete)

https://powderriverordnance.com/shop/m3 ... 4485ae434a

[Elwood]

Does anyone have any pictures of the entire pump and lines to where they go. Where it is mounted on the dash, and how it connects to the carb or intake??

Thanks
Steve

Here's an old thread with a series of good detail photos by Storm Stevenson (who sadly passed away in April 2019, his forum name was "52 M-42") showing the primer installation on his M37.

http://www.g741.org/PHPBB/viewtopic.php ... 795#p41795

Here's a photo I posted years ago (seems to have disappeared when the image hosting changed) that shows the kit contents with individual part numbers.

Engine Primer Kit Contents reduced size.jpg (104.14 KiB) Viewed 1095 times

[sturmtyger380]

Or..... you could do like a guy I know that has a hard starting halftrack. He added a port on his dashboard with a line to his carburetor intake. When it won't start after a long time sitting, he takes his spray can of ether, puts the straw tube in the spray head, inserts that into the port and sprays in starting ether.

[Cliff]

My M-37 ( 1953 ) has the stock military fuel pump that has a priming arm. My understanding is that the military required that feature for the very reason that these trucks sit a lot in the military so they wanted the GI in charge of the vehicle to be able to lift the priming arm a few times to prime the fuel pump when the truck had been sitting so it would start. As a previous post said he has an electric fuel pump that he put on his truck so that it would automatically prime the system. Doesn’t the priming arm solve the problem if the system is dry from sitting?

[Elwood]

My M-37 ( 1953 ) has the stock military fuel pump that has a priming arm. My understanding is that the military required that feature for the very reason that these trucks sit a lot in the military so they wanted the GI in charge of the vehicle to be able to lift the priming arm a few times to prime the fuel pump when the truck had been sitting so it would start. As a previous post said he has an electric fuel pump that he put on his truck so that it would automatically prime the system. Doesn’t the priming arm solve the problem if the system is dry from sitting?

The manual priming lever on the fuel pump is only going to push fuel into the carburetor float bowl, and even with a full bowl, the slow speed jet and choke can only enrichen the mixture so far. The cold weather priming pump injects gasoline directly into the intake manifold, making the air/fuel mixture even richer going into the cylinders when the engine is cranked over in cold temps.