New Owner and I Already Broke It!

[NCM]

Hello everyone,

I posted a few messages here in the past when I was looking for an M37. I'm happy to say I pulled the trigger on a 1954 out of Colorado. Rust free, and seemingly good mechanical condition.

Tonight I was out on my third drive since I bought it. On the way home it started sputtering, and finally died as I coasted into my driveway. Now it won't start at all. I'm going to poke around tomorrow, but I was wondering if anyone had any suggestions on where to start? I will check to see if the spark plugs are getting spark, and then if the fuel pump is working.

Oh and I should mention that I am a newbie when it comes to working on cars. One of the reasons I got the M37 was to learn how to work on them; I just didn't realize how soon I would need to start!

David

[W_A_Watson_II]

First I'd guess fuel, the filter likely plugged?

Second I'd guess electrical, likely the old wire gave out?

[w30bob]

Hi David,

Welcome to the fold. Don't worry.........you didn't break it........your truck is just letting you know who owns who. These trucks are almost as simple to keep running as an old tractor. It's just fuel, air and spark. The folks on this board have enough experience with these trucks to solve any problem you could possibly have. So take a good look at the ol' girl tomorrow and tell us what you find. Since you're a self-proclaimed newbie when it comes to working on cars................if you do decide to pull a plug and check for spark........just make sure YOU are not the ground path while you're holding that plug......or you're going go get zapped! Don't ask me how I know that..........we were all newbies once!

Here's what I'd do............first just try to start the truck like you normally would. If it starts up that tells you the problem is either something that degrades with time or with temperature. Things that come to mind are a bad ignition coil, or crap in the fuel system. If it doesn't even turn over then either the generator died and you were driving on battery power (until they were drained and the engine quit) or the regulator died. If the starter cranks normally but the engine won't start it's time to look to see if you have fuel and spark. If it starts but runs crappy or dies it's going to be a bit more complicated to figure out.

Let us know what you find.

regards,
bob

[RMS]

m37 was my first vehicle and I didn't know a starter from a carburetor. you are in a good place as you will have no preconceived ideas on how things should work. let us know what you find.

[ZGjethro]

I'm putting my money on a spark issue, with no info about your truck to base that bet. When I bought my truck in 2009, it barely ran, but it was a combination of clogged up carb and bad tune/timing. I sent the carb and distributor to M-series rebuild. The carb was cleaned and rebuilt, and I had a Pertronix electronic ignition installed. You can probably do a lot of that yourself with a bit of research on the correct components (ethanol).

More recently my coil went bad, even with all the vent lines to the distributor in place, and the correct fittings in the carb throat. That would be my first guess, if the truck just dies and won't start. There are plenty of threads about the coils on this site if you search a bit.

Good luck, and keep us posted on your progress

John

[Cal_Gary]

I'd also check to make sure your fuel tank is vented. If it was running then sputtered and died, fuel starvation is a possibility. If you get it started again and it sputters and dies, quickly go remove the fuel cap to see if you get a big release of vacuum. If so, you've got an issue with the fuel tank vent. Also check the fuel tank cap-some are switchable to non-vented for fording and would cause this problem as well.

Congratulations on your purchase!
Gary

[just me]

I'm gonna bet fuel related. And if you don't do the whole job from tank to carb you will just waste time and money.

[NCM]

Thanks for the input everyone. The update this morning is that it reluctantly started and ran very rough. It was very hard to keep it running. The fact that it stated at all makes me think it's electrical related, possibly the points or coil?

[NCM]

Further update: I checked each individual plug for spark and they are all good. I then tried starting it again and it fired up, although with a bit of hesitation. Now the issue is that if you press the accelerator down too quickly it wants to die. Slow application of the gas yields a smoother rpm increase. Now I'm thinking it may be a carb issue.

I should note that this truck did a lot of sitting over the last decade before I bought it. Additionally, when I got it I put gas in that has ethanol. Not sure if that matters.

[Elwood]

Since you mentioned that one of your objectives in purchasing the truck is to learn how to work on it, consider purchasing the military manuals that apply to it, if you don't already have them. The search function here is a good place to find info, and here's one topic to start: http://www.g741.org/PHPBB/viewtopic.php ... als#p61509

There's also a specific military manual for the Carter carburetors (assuming that your truck still has the original type carb): TM 9-1826A, Ordnance Maintenance Carburetors (Carter)

Just use some caution with the scanned manuals (in lieu of the paper versions); the scanning process sometimes doesn't pick up text or incorrectly converts it, especially with fractions or small print. I have both, but use the paper copies almost exclusively.

As for your carb, it could be a problem with the high speed circuit, or perhaps with the bowl vent being plugged. Long periods of sitting, especially with newer gasoline, can gum things up inside the carb. If gas with ethanol is the only fuel you can get, then a carb rebuild with newer, ethanol tolerant gaskets and seals is advisable. Just be sure that you're buying new parts made for use with ethanol, not some new-old-stock kit that was made years ago. These guys should be able to help you: http://then-now-auto.com/

Also, have you checked for an intake vacuum leak on the engine?

[NCM]

Elwood, fortunately I received a printed manual with the truck. I have found it very useful in terms of describing how to take things apart and put them back together, but less useful in terms of diagnosing problems.

I am definitely stumped so far. It will start right up and I can rev it in my driveway, but when I try to drive it around my neighborhood it eventually sputters and dies and won't start for about 20 minutes or so. Some searches on this site uncovered vapor lock as an issue for others with similar symptoms, but it is in the 70's here so it seems unlikely that my truck has that issue.

[w30bob]

Hi David,

Ok, so you're confident it's the fuel system issue. I wouldn't rip that carb apart just yet though. You said this problem started on your third drive...........so I assume you're saying you had no engine issues during the first 2 drives, correct? Assuming this problem just popped up at the end of your third drive........something changed. Or accumulated. What I'm saying is your whole fuel system is suspect, not just the carb. Carbs don't work fine one moment and then work like crap the next unless something changed. If a bunch of crap made its way to the carb, then rebuilding the carb won't stop it from happening again. If it were mine I'd start at the tank and check the whole fuel system out. I'd want to see what the inside of the tank looks like. Early tanks had a drain plug that you could just remove and see what comes out. The tank also has two partitions inside it to stop sloshing, so when you look into the sender or vent hole you can only see so much. But if you see any rust or debris in the part you can see.......you know you have a problem. If it checks out clean I'd disconnect the fuel line at the tank and fuel pump pump and blow compressed air thru the line from the tank side. If you find any crap you have to make sure it's all out. Once all that's good I'd check out the pump.

There's a priming handle on the stock pump that can come in handy when checking the pump diaphragm. You mentioned the truck ran but wouldn't accelerate quickly...........a sign of not enough fuel. If the pump is going south it can be dumping fuel into the engine crankcase.........so pull the dipstick and make sure the oil level isn't higher than normal. If it is high don't run the engine anymore or you risk ruining it. You'll need to find the fix the fuel pump and then change the engine oil. If the pump checks out good.......make sure the line from the pump to the carb is clear. Then all that's left is the carb. When you open it up it should be rather obvious why it's not working properly.

I know what I'm suggesting is a lot of work. But if you plan to keep the truck, knowing the condition of the entire fuel system will give you "piece of mind" and eliminate those components from future investigation when another problem pops up (and another one always does). As with everything on this site.........that's just my opinion, and we all know what an opinion is worth.

OOOOPS! While I was writing this your newest post popped up. Whenever someone says it ran for 20 minutes or so we all start thinking the vent on the gas cap is closed. Check your gas cap and make sure the vent is open!

regards,
bob

regards,
bob

[NCM]

Thanks Bob, that's a good action plan. My gas cap does not have a vent on it like some of the other ones do.

[ashyers]

When it sputters and dies check to see if you have fuel in the float bowl. You can do that by pulling the fuel bowl drain. Just make sure you don't douse the hot exhaust with fuel. That will also give an idea of how much sediment is in there.

[ZGjethro]

Just as a preventative measure, check your oil if you are running the original fuel pump. The rubber parts in it are not ethanol compatible, and if a diaphragm gets cracked, gas can flood your crankcase, thinning your oil. Make sure your oil doesn't smell like oil. Lots of owners change the mechanical fuel pump to an electric pump, usually located back by the gas tank

A symptom of a bad coil can be temperamental ignition. As the coil heats up, it starts to intermittently fail. My truck kept stranding me 10 minutes from home before I put in a new coil.

It could easily be gunk in the carb also. Especially if it sat for a decade