Is my m998 motor toast?

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Is my m998 motor toast?

Post by Kurtshalftrack » Mon May 07, 2018 5:19 pm

Buddy used my 6.2 HMMWV...he said the ideal ran away full throddle for about five minutes and he could not get it to stop..then beltched black smoke from the exhaust and stopped. Like a dumba ass he cut the battery cables to try to stop it. So now I have no idea if he blew the motor. No leaking out or noticeable damage. Thoughts?
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Is my m998 motor toast?

Post by DockRocker » Mon May 07, 2018 5:29 pm

Put a bar on it and see if it will turn over. Then drop the oil pan and check the mains.

If that checks out then hook it up and see what happens when you turn it over. If it’s hurt it will still he hurt. It it’s not hurt the. You will know.


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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Mon May 07, 2018 7:06 pm

Thank you. What do you mean put a bar on it? I will drop the oil pan and see what I can tell. Thank you again.
Kurt
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Re: Is my m998 motor toast?

Post by lkgindy » Tue May 08, 2018 2:01 am

My first question is why it would run away. Was the tank filled with gasoline or was the truck sitting next to something giving off large amount of gasoline or some other vapor?

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Re: Is my m998 motor toast?

Post by DockRocker » Tue May 08, 2018 2:26 am

Kurtshalftrack wrote:Thank you. What do you mean put a bar on it? I will drop the oil pan and see what I can tell. Thank you again.

Put a breaker bar or long handles socket with a cheater pipe on the crank bolt and attempt to rotate the motor over and make sure everything will work without having to hook up the starter. This will tell you if the engine seized.

Also the poster above me is right. Why did the motor run away in the first place?


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Re: Is my m998 motor toast?

Post by dilvoy » Tue May 08, 2018 11:10 am

I've run 50% gasoline in a 6.2 for ten miles when I could not find diesel and it ran just fine, just clattered more. The advance mechanism might have done something weird from low fuel pressure under the top cover of the IP, but advance only raises RPM just so much. The throttle needs to be moved to really raise RPM's. Could that engine be so old and worn that it started to run on oil blow by? Hard to believe unless it was a real smoker before this incident. How much do you trust your friend or the good looking girlie he let drive it to not have driven too fast for too long on the road?
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Re: Is my m998 motor toast?

Post by Action » Tue May 08, 2018 1:48 pm

Look to see if the big spring on the injection pump is rusty and broke. driver side.

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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Tue May 08, 2018 4:44 pm

All,
Thank you for the input. I trust him enough to never let him use my toys again. I was overseas at the time and he was “looking after it for me. It had 14k original miles and did not smoke except upon initial star up. He said the throttle cable came off once before. No idea why it would run away like it did. He said he pulled it out, it started fine, he got out to load an ice chest and it began to run like someone placed it in nuetral and had their foot on the gas. He opened the hood and could not determine what the issue was, he cut the battery cables and of course that did nothing to stop it. He stated it ran at full throttle for 5-10 minutes then started blowing black smoke and stopped altogether when he ran to get a fire extinguishing as he thought it was going to catch fire. I did notice a few very small black spots that look like soot that blew out of the exhaust pipe, they are on the paint and don’t wipe off. Looks like someone misted the are with black spray paint. That’s what he said...he also said he would pay to fix it...but I have not seen a dime yet and that was 3 years ago. I will try to turn the motor tomorrow ..will advise then. Thank you again...anyone got a line on a motor near Virginia ...Quantico ?

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Re: Is my m998 motor toast?

Post by Retired War Horses » Wed May 09, 2018 6:40 am

I had a truck do this, the return spring came unhooked somehow, pulled up to a light and it just would decrease on the RPM’s and I was braking, almost ran into the car In front of me....quick thinking, I flipped it into neutral and killed the motor.

I just had a truck at the base that had a bad fuel cutoff solenoid, turned the switch to off and nada....kept running, I gave the top of the pump a whack with a hammer as it turned off, this in conjunction with a bad solenoid would be your issue, but I don’t see how both would fail at the same time....I assume he tried to turn off the ignition?
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Re: Is my m998 motor toast?

Post by Action » Wed May 09, 2018 8:39 am

This happened 3 years ago ?

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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Wed May 09, 2018 5:15 pm

Yes about three years ago while I was overseas and it was parked in a garage. So I dropped the oil pan, oil is dirty but no significant metal shavings or other debris. Oil does not smell burnt. The motor turns, I can turn in with minimal force on the fan blade, coolant is fine. The two smaller belts are off the generator and hanging loose. No leaks etc. at the top of the engine near the throttle cable is a rubber boot with a line through it goes to a peg. The line is not attached the peg...but clearly should be. Could this have caused the issue? O
Kurt
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1952 M37
1984 M998
M100
America is still the greatest country on earth...don't give up the fight!


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Re: Is my m998 motor toast?

Post by dilvoy » Wed May 09, 2018 5:30 pm

Are you talking about a rubber hose that comes brings return fuel from the injectors and curves rearward towards the top of the injector pump and attaches to a fitting?
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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Wed May 09, 2018 5:35 pm

No it is a not a hose it is a push pull rod similar to a throddle cable..goes straight down from the top center of the motor and has a 3 inch accordion rubber boot around it. It has a loop at the end that slides over a peg that looks as though it should have a retainer pin to old it on .retainer pin / ring is missing. Does that help? Appreciate the help.
Kurt
1943 M3 Halftrack
1952 M37
1984 M998
M100
America is still the greatest country on earth...don't give up the fight!


San Diego, CA

Kurtshalftrack
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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Wed May 09, 2018 5:38 pm

If I start this thing up and it starts to idle night or run away what it the quickest best way to stop it? Suffocate it or remove fuel line? Thoughts appreciated?
Kurt
1943 M3 Halftrack
1952 M37
1984 M998
M100
America is still the greatest country on earth...don't give up the fight!


San Diego, CA

Kurtshalftrack
G-Command Sergeant Major
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Posts: 220
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Re: Is my m998 motor toast?

Post by Kurtshalftrack » Wed May 09, 2018 5:46 pm

If I can figure out how I will post a picture of it....got a message saying my photo file was too large.
Kurt
1943 M3 Halftrack
1952 M37
1984 M998
M100
America is still the greatest country on earth...don't give up the fight!


San Diego, CA


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