engine dies after 3 min

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rickf
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Re: engine dies after 3 min

Post by rickf »

Is there some reason you refuse to believe the coil can be your problem? The coils on the M series vehicles are famous for this problem. If it were me I would at least run a diagnostic on it. OR, you could rebuild the carb again. :roll:
1953 M37
1964 M151A1
1967 M416
1984 M1008
4/1952 M100
12/1952 M100 gone
ez8
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Re: engine dies after 3 min

Post by ez8 »

markkish79 wrote:I did a vacuum check today and it was a steady 15 psi. What is the standard pressure I should be getting, anyone know?
17-21 inches of mercury is a standard reading.
Your reading of 15 (and I'm hoping you meant to say inches instead of psi) means you're either a couple thousand feet above sea level, your rings are worn or your oil needs changed.

You can get more information on how to read a vacuum gauge from this link: http://oldjeepcarbs.freeforums.net/thre ... read-first
rickf wrote:Is there some reason you refuse to believe the coil can be your problem? The coils on the M series vehicles are famous for this problem. If it were me I would at least run a diagnostic on it. OR, you could rebuild the carb again.
Do you have the gumption to remove the distributor, markkish79? Running a bench test on the coil isn't going to hurt.

If you installed your carb on your buddy's truck, does his truck run? If so, you can eliminate the carb from your problem.

Someone once told me, "If a human being built it, a human being can fix it." Just remember, these are basically big lawn mower engines. There's nothing magical about them. You just have to eliminate possibilities of what could be wrong.

Good luck!
markkish79
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Re: engine dies after 3 min

Post by markkish79 »

rickf wrote:Is there some reason you refuse to believe the coil can be your problem? The coils on the M series vehicles are famous for this problem. If it were me I would at least run a diagnostic on it. OR, you could rebuild the carb again. :roll:

I did check the coil, I'm sorry I thought I mentioned this. The coil is good and although this is a classic sign of the coil going bad, the engine revving up high before cutting off is not due to a coil failure. thank you for the feed back though. I'm slowly getting there. The only reason I took the carb apart so many times is because I feel like I missed something. I had another carb on there last week and it worked.
rickf
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Re: engine dies after 3 min

Post by rickf »

Ah, You failed to mention a different carb worked. You need to put these details in so we can stop wracking our brains trying to figure out your problem. You now know it is definitely the carb.
I know that the flare before dying is not indicative of a coil but you had the carb apart numerous times with the same results so you have to start looking somewhere else. This is where you failed to mention that a different carb had worked well.
1953 M37
1964 M151A1
1967 M416
1984 M1008
4/1952 M100
12/1952 M100 gone
just me
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Re: engine dies after 3 min

Post by just me »

Using the same gaskets over and over isn't helping and may just be the issue. The top gasket forms a large part of the fuel circuit for both idle and steady state driving.
Here is a link to download the military manual from Radionerds. Chapter 10 starting at page 101 is the tank carburetor and ETW1.
Http://www.google.com/url?q=http://radi ... QsVwM_TQug
"It may be ugly, but at least it is slow!"
markkish79
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Re: engine dies after 3 min

Post by markkish79 »

It was brought up twice that a different carb was installed and fixed the problem. That's why I kept focuse on the carb and took it apart so many times. While complying with everyone's suggestions of checking other systems.

Thanks everyone for trying to help me out on this issue. I'll leave you guys alone on this one. When I figure it out no matter how stupid of a fix it is, I'll post it. Thanks again, Mark
NAM VET
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Re: engine dies after 3 min

Post by NAM VET »

no harm, no foul, I just spent over two hours trying to figure out how to re-install the fuel filler neck in my truck. I kept saying to myself "it came out of here last fall, it has to go back in somehow." Tried from the outside, inside the bed, from below, again and again. Then all of a sudden it just clicked into place, where I could tighten the clamps and bolt it in. Then needed to better align some of the clamps, and turned the neck a bit, then once again, I just couldn't get the darn thing to slip into place. Another most of an hour, and finally just decided that I had to take off the big and small short hoses, and in a few minutes, it slipped into place, and I bolted it all in, and aligned the gasket screws where I could get to them. All in all, a three hour project to "install fuel filler neck, and secure with screws...."

I am tired now, maybe a nap. Getting hot outside and I don't do well in the heat in the sun.

and please do let us know how it all works out for you.

NV
ez8
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Re: engine dies after 3 min

Post by ez8 »

I got thinking about this some more and I'm wondering if it isn't your float in the carb. If the float got stuck in the empty position, you'd have more gas than necessary getting into the intake which would cause a brief surge and then nothing. The difference between your carb and your buddy's is likely here. Play with it a little and see.

edited to say "float" instead of "float valve"
vargaspj
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Re: engine dies after 3 min

Post by vargaspj »

I wonder if the fuel pressure at your carburetor fuel bowl may be off (too high?).
The original mechanical fuel pump by spec delivers 4 to 5-1/4 psi.
The original mechanical fuel pump has no filter between it and the fuel bowl so the max fuel pressure at the bowl should be 5-1/4 psi or less.
The float if adjusted correctly constantly moves up and down and lifts and drops the needle on the fuel inlet seat to keep the fuel flow and the fuel in the bowl at the correct level during normal operation.
Excessive pressure at the fuel bowl can "overwhelm" the float during operation causing excessive fuel into the carburetor from the float bowl.
Depending on the float level setting, this may not occur immediately but it may take some time of operation before occurring.

You have installed an electric fuel pump and have multiple filters on your fuel line.
Take the pressure delivered by your electric fuel pump and subtract the pressure drop added by each inline filter to estimate the fuel pressure at the fuel bowl - is it between the original 4 to 5-1/4 psi?

Note when the problem occurs according to the speed of the vehicle and the carburetor circuits:
1. 0 to 20 mph uses the carburetor Low-speed circuit.'
2. 20 to 30 mph uses both the Low-speed circuit and the High-speed circuit.
3. 30 to 50 mph uses the High-speed circuit.
Is the problem occurring in one of these regions? If it is it may help to isolate the issue to one part of the carb.

Rebuilding the carb is not a trivial issue and something minor during rebuild can render a carb almost useless or operating erratically.
I would strongly NOT use a carburetor kit designed for another carb to rebuild this carb; ONLY use a carb kit for the ETW-1.
If you put an ETW-1 carb on from a friend and that solved the issue you may consider:
Having your carb rebuilt by a professional carb shop or M-Series Rebuild or Vintage Power Wagons.
Purchasing a professionally rebuilt ETW-1 from M-Series Rebuild or Vintage Power Wagons.
If the carb kit is 50-60 bucks each I would stop the rebuild effort and have it rebuilt by a pro or buy one rebuilt as noted above.
You may be repeating some small mistake or issue each time you rebuild it.
There's NO shame in calling in the pros on a 60+ year-old vehicle using obsolete technology.
I'm sure M-Series Rebuild or VPW can help; that's why they're in business.
rickf
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Re: engine dies after 3 min

Post by rickf »

It is also possible that the carburetor core is bad and you will never get it right. If it is cracked or warped internally then there is nothing you can do, it is scrap. Even the pros throw them out.
1953 M37
1964 M151A1
1967 M416
1984 M1008
4/1952 M100
12/1952 M100 gone
NAM VET
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Re: engine dies after 3 min

Post by NAM VET »

While my carb seemed to be running fine, when I decided to pull my motor for a full rebuild, I took my complete carb (and starter, 100 amp alternator, and fuel pump) up the 100 mile drive to Charles Talbert's place, and went back a month later to pick them up. All I can say is my carb and elbow and such came back as new. I just put it back on recently, and have had perfect running since. I wasn't about to mess with it. I am good with Holley's, but this was just too much for me to tackle.

Sometimes we just need a pro to do something.

best wishes,

NV
mdainsd
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Re: engine dies after 3 min

Post by mdainsd »

Hello new guy to forum here. But did my first M43 build in '68.

The revving up before dying is a mixture going way lean as in running out of gas.

Have you done this one little thing: Disconnect the fuel line from the carb. Remove the seat fitting from the carb. Look in there real close from the fuel line side. Is there something that looks like a tiny hairball in there? Ive found that in more than one of these carbs.

While you have the fuel line off the carb, hook your vacuum gage to the line. Most vacuum gages are compound, so they read vacuum going one way and pressure going the other. You might want to to this cold. then again after a stall out.
ZGjethro
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Re: engine dies after 3 min

Post by ZGjethro »

If you have ruled out the coil going bad (my first guess), have you considered a gas tank venting issue? Any chanc your gas cap is in the fording position and the tank isn't venting? My dirt bike had a gas cap recall since a chech valve in the tank would fail and the tank would not vent, resulting in no fuel flow
just me
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Re: engine dies after 3 min

Post by just me »

ZGjethro wrote:If you have ruled out the coil going bad (my first guess), have you considered a gas tank venting issue? Any chanc your gas cap is in the fording position and the tank isn't venting? My dirt bike had a gas cap recall since a chech valve in the tank would fail and the tank would not vent, resulting in no fuel flow
The cap on an M37 is non venting. The vent is a line from the tank to the carb inlet air horn. (That could be plugged)
"It may be ugly, but at least it is slow!"
ZGjethro
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Re: engine dies after 3 min

Post by ZGjethro »

I'm not near my truck or any of my manuals, but I could have sworn my early model truck has a two position gas cap. I could easily be wrong on that. My vent line is open in the engine bay and is not hooked up to the air horn
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