m37 won't stay running, won't restart

[jepsonjj]

I just posted a similar thread in the wrong spot. Here is the situation.
- truck ran great when stored
- truck stored for 4 months in garage
- truck started up nice drove it across yard idled fine then quit
- checked fuel (not empty) added fuel, wouldn't start
- pushed truck into garage, started 2 days later
- quit again just like before - after warming up
- repeated this sequence 4 times, always quits
- I can keep truck running if I play with throttle or pull throttle out to high rpm but sputters some
- if the truck is shut off, or quits, it won't fire

note: I have been running the truck with vent lines unhooked, is this the problem?

Does this sound like a fuel issue or ignition?

Any help would be appreciated.

Thanks,

Joe

 

[MilitaryRestoration]

Sounds like fuel pump problem maybe... the diaphragm in those original fuel pumps get eaten up by 'todays' gasoline... maybe that or not enough pressure going to the fuel tank itself... do you have a clear inline fuel filter on it? if so check and see if gas is even getting up to the carb. you can also pour some gas down into carb and see if it runs fine on that and then if does, it's more like a fuel problem not getting to carb

 

[jepsonjj]

Thanks for the reply. I have a renewed tank, new lines, new inline filter, new fuel pump, and a new carb. None of this has changed since parked. Gas is definately getting to carb. I drained the carb to check for water, but the fuel has stabil in it, and I didn't find water. Could it be the coil?

Thanks again,

Joe

 

[ctmustang]

it could still be the fuel pump getting gas just not enough enough pressure.
also check for condensation in electric connections.but really sounds like a fuel problem

 

[bpj911]

I would replace the condenser and check the points carefully. If that isn't it then I would swap the coil with a known good one. good luck. It's usually an ignition problem before fuel.

 

[stampy]

Check your ground wire to the battery and the motor. I had a dirty ground on a car drive me crazy for about a week.

 

[mhassett]

Engibe Quits

Check the carburetor float level.
Mine acted very similar with a new carb.
MHassett.

 

[longshot2171]

Mine did the same thing last week after sitting in the garage for a couple of weeks.. Started up, ran for a minute, sputtered and died. Wouldn't restart. The carb seemed to be flooded. After some head scratching, foud that the little check valve in the fuel line by thf float had some gunk in it and wad jammed open. I blew it out, cranked the engine for a couple of seconds and everything seems fine now. Time for a new fuel filter......

 

[ton10291]

I had a similar situation and it turned out to be a vacuum leak. I had replaced the fuel pump but hadn't reconnected the vacuum lines.

 

[bpj911]

Everyone is saying fuel but I say ignition. Check it carefully. Usually when things don't run right when warm it's ignition in my experience.

 

[jepsonjj]

Thanks for all the replies. Just thought I would post an update and ask opinions again. This is what has transpired.

- Changed the cap, rotor, points and condensor. I already had these new parts.
- Couldn't even get spark.
- Talked to Charles Talbet, and arranged to have electronic ignition done, but
- Intalled old cap and rotor with new points and condensor and she started
up without the choke.
- Adjusted the timming, drove it about three miles, never ran so good.
- Returned home, shut her off and she wouldn't restart.
- Tried the choke, no good
- Truckn sat about 4 hrs while I trimmed trees.
- Went to start her up and she fired immediately, what the #*@*%?????
- Carb seems to leak a little around the gasket when I try to start her warm
- As long as she is cold, she will start and run but not when hot.


Any more ideas?????

The fuel pump and carb are both reconditioned with what I think are modern gaskets.



BTW - I purchased what I was told was a NOS distributor in Dayton at the nationals a few years ago - I was robbed. Buyer beware, I tried this distributor before and had no luck. The timing was off by about 160 degrees so I shelved the main body and shaft, now I know the cap and rotor are no good. I have $100 in a set of points. I wish I new who the fella was that sold it to me.

Thanks to everyone

Joe Jepson
1952 M37

 

[bpj911]

Did you change the coil? When you go to start it when warm are you holding the throttle about 1/4 -1/3 open? A lot of these will boil the gas over into the manifold when shut off hot. I hold mine about 1/3 open and it fires immediately. If I don't it typically will start but not immediately. Good luck.

 

[jepsonjj]

No I didn't change the coil, but if the coil was bad, why would it stay running when hot but not restart? I have tried starting the truck with and without the throttle part way open - same result. One thing I did notice, was a slow girggling - pulsating sound coming from the intake. Like you said boiling over sound. I was thinking of shutting the gas off just before shutting the truck off to see if that helps. Could this problem have anything to do with the vent in the fuel cap?

Sure appreciate the help!!!

Joe Jepson

 

[EZFEED]

A coil can go bad and still work occaisionally. One of the internal windings may have broken and is giving you this trouble. One of my Farmalls had this problem. The tractor would crank up fine but once warmed up it would sputter and kick erradicly then eventually die. Changed the coil with a high vibration one and it fixed the problem. All of that rough ground that I run over while mowing played its hand on killing the coil. I took the old one apart and found it broken in the inner winding. Just that little bit of heat would cause it to expand then lose the circut.

Also might want to check your car. If fuel has been allowed to set in the carb for a while it's probably varnished up and sticking.

 

[bpj911]

Coil

Hot starting is usually an ignition problem. Check to see if you have a fat blue spark when it's refusing to start. I would guess you have weak spark when hot. As far as fuel boiling over, check your winter/summer selector first. All the way forward is winter if I remember right. So, push it back for summer. I usually leave mine halfway all the time.

Despite the carb being overhauled, perhaps your float is too high. You may have a combination of problems. Good luck!

 

[Bill W]

Did you do away with the supression filter thats located at the base of the dist behind the threaded Power supply plug? ( 4 screws hold it in the dist) these get saturated and give the symptons of a bad coil., I modified mine so I could still use the plug ( see pic )

 

[jepsonjj]

I wanted to say thanks to all of you that posted replies. I changed the coil tonight and the truck runs well, starts right up after it is hot. Back to the body work.

Joe Jepson

 

[bpj911]

good news

Many a fuel problem has been solved by checking the ignition...

 

[militarytrux]

If you have'nt already change the coil and get an electronic ignition module from Pertronix it will cure any ignition issues you may have, I installed both pieces on my M37 4 years ago and she starts within 2 to 3 revolutions everytime, no more cranking till the cows come home to get her to fire.

 

[m3751]

My '51 M37 has had the same issues lately; starts immediately at times then refuses to start again. The M37 stranded me a few times requiring it to be towed home in disgrace. This situation was really frustrating me. Based on advice from a number of folks I started with the fuel system first. Nothing I did, replaced or checked seemed to make any difference. I then turned to the ignition system.

I replaced the coil, the distributor, rotor and sparkplugs and while I was at it I replaced the points and condenser with a 24V electronic ignition (MV-161 from Pertronix).

It now seems to work very well. Over the course of a few days I started the truck about 10 times and went for a number of drives around the neighborhood with absolutely no issues.

The addition of the MV-161 seems to really make a difference. Previously when the vehicle was running, if you press down on the accelerator invariably it would hesitate a little before responding. With the new MV-161 in place, the increase in engine RPM’s is very smooth and responsive to the accelerator. I also experienced a significant feeling of increased power from the engine as it would actually accelerate briskly in the higher gears.

The installation of the MV-161 was extremely easy; I just removed the old points and condenser and installed the new electronic ignition module, cut the wires to reach to the new coil and installed the crimp lugs. The wires are attached to the coil, Red to positive (along with the 24V wire coming from the ignitor connector) and the Black going to the negative. I then placed the magnetic actuator on the rotating shaft and placed a new rotor on the shaft. The mechanical fit of the MV-161 was perfect; this device was clearly designed for this application. At this point I also replaced the distributor cap. The M37 technical manual indicates you should remove the ignitor assembly to do this work, but I managed to do all the work without removing the assembly, it’s a little tight but doable. When I was done with the installation of all the new parts I put everything back together and unbelievably on the very first try the engine came to life. Since I had not removed the ignitor assembly I was lucky that the timing was still good enough that I did not have to make any adjustments. If you’re a purest you might want to stick with the points and condenser, but the electronic ignition made such a big difference that I would highly recommend it to anyone. Once installed, it is out of sight and no one would even know it there. The unit is a bit expensive, but considering how well the engine now performs I think it was well worth the investment.