spark plugs

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rickf
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Re: spark plugs

Unread post by rickf » May 4th, 2018, 4:49 pm

Does it die again not long after getting it started? Does it backfire out of the exhaust as it is dying? Sounds like a bad coil.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

tecknomage
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Re: spark plugs

Unread post by tecknomage » May 6th, 2018, 1:14 am

dies sometimes... never back fires.
was a pill to get started again going up a small hill.. Hmm, fuel pump? the "electric" pump in photos was gone when I got the critter. But for what its worth, she's got a home now where I'll do my best to get her going.
Have a foot race/get together end of month, memorial day, & a lot of nam era veta @ local homeless shelter here. Was hoping to get her going to where I could shuttle them over to the events. Thought it'd be a cool thing to do. try to take a load of biscuits & gravy over once a week or so,. Talk about happy.....you'd think I was handing the guys gold bricks..

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Re: spark plugs

Unread post by rickf » May 6th, 2018, 8:59 am

What kind of fuel pump is on it now?
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

tecknomage
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Re: spark plugs

Unread post by tecknomage » May 7th, 2018, 10:32 am

"standard" , mech pump, again, was "supposed" to be "new". Then was supposed to be fully restored, supposed to be an A2, supposed to great running cond, supposed supposed .. see a pattern here?
ANYWAY, worked EMS this weekend, they were short people.Only 1 crew... Lord.... Didn't get a chance to work on her. BUT, because I was there, Lord blessed me.. there's an 8 month old child that will still get to know its Dad. & a Preacher's wife that'll be back in church next Sunday.. Days like that that make it all worthwhile, & realize just HOW meaningless things like a bad running MUTT is.. Feel like the Almighty needed to smack me up against the side of the head.
Lord... realized I still have EMS BDU's on... got in this morning , found my cat sick , got a clean shirt took her to the vet & went on to work..So Im stuck @ work with bdus with reflective stripes .. lol

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rickf
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Re: spark plugs

Unread post by rickf » May 7th, 2018, 6:01 pm

Well, I guess that can be good or bad depending on what "work" is? Hopefully pet is alright and yes, helping people out puts a lot f things in perspective. I did EMS long before it was called that back in the 70's. Things were a lot different then.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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Re: spark plugs

Unread post by Surveyor » May 7th, 2018, 9:57 pm

Have you checked that fire is on each plug? New fuel or old? Clogged filter or line? Carb out of adjustment? Valves adjusted? Timing correct? Might want to follow the rickf list...

viewtopic.php?f=3&t=2395
rickf wrote: back in the 70's. Things were a lot different then.
I was just a kid!. Still remember sitting in front of the 3' thick tv watching Emergency! Wish I still had my old lunch box...

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1960 M151 Run #1
"There is one nut on a M151 that is very difficult to remove....." - K8icu
"She ain't a Cadillac and she ain't a Rolls, But there ain't nothin' wrong with the radio" - Aaron Tippin
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acudanut

Re: spark plugs

Unread post by acudanut » May 7th, 2018, 10:21 pm

Back in the 70's a Ambulance and a Hearst were the same vehicle. :shock:

tecknomage
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Re: spark plugs

Unread post by tecknomage » May 16th, 2018, 12:53 pm

yes, voltage to every plug. coil MAY be weak, according to 1 person. no valve noise, so hopefully that isnt issue.

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Re: spark plugs

Unread post by tecknomage » May 16th, 2018, 12:58 pm

tecknomage wrote:"standard" , mech pump, again, was "supposed" to be "new". Then was supposed to be fully restored, supposed to be an A2, supposed to great running cond, supposed supposed .. see a pattern here?
ANYWAY, worked EMS this weekend, they were short people.Only 1 crew... Lord.... Didn't get a chance to work on her. BUT, because I was there, Lord blessed me.. there's an 8 month old child that will still get to know its Dad. & a Preacher's wife that'll be back in church next Sunday.. Days like that that make it all worthwhile, & realize just HOW meaningless things like a bad running MUTT is.. Feel like the Almighty needed to smack me up against the side of the head.
Lord... realized I still have EMS BDU's on... got in this morning , found my cat sick , got a clean shirt took her to the vet & went on to work..So Im stuck @ work with bdus with reflective stripes .. lol

well, since then, Devil SURE has been riding my back. 1500 worth of vet bills, City argue over a tree.. then lost rescue cast last night.. U name it, its gone bad. Saved 2 people, & guess devil really didnt like that , huh

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Re: spark plugs

Unread post by m3a1 » May 17th, 2018, 1:30 pm

I've reviewed your postings. Sounds like you're experiencing the bulk of your problems under a load and from that I conclude you probably have a air/fuel mixture issue or fuel delivery issue.

Start with the easiest check. Is your carburetor firmly seated and bolted down? No, seriously! Give it a little wiggle. If it's not..I guarantee you it's a big part of your troubles. You might be surprised how often carbs are found to be loose. People get busy and forget to tighten them down. It happens.

Is there fuel coming into your fuel filter? If you don't have a clear, disposable fuel filter, get one and install it. Actually, get two (one for later). Yeah, yeah...I know. They don't look cool. Neither does being stopped on the side of the road with the hood up. Yes, you can keep the metal fuel filter but replace it with new. Cheap insurance, right? NOW does it run better?

Examine the spark plugs. They may show evidence of running in a lean condition. Have you looked at them? Look for white powdery residue on the plug or plugs. If they are ALL showing a lean condition it's a general lean condition. If only ONE plug is showing lean, then the problem is localized to that cylinder or that plug.

But let's assume all the "supposed-to work fine" stuff is true and correct and you simply have an emerging condition. It happens in old cars and trucks, especially when change of ownership means a change in the manner or frequency of its use. By way of example, since I started driving my old MUTT regularly (far more frequently than the previous owner) little rust particulates in the tank are starting to break loose from all that fuel slowing around and those get into my fuel filter. With a clear plastic fuel filter, I can see it and get a general idea of when it's time to swap it out.

From a cold start, if your engine is reluctant to start, it may be timing or valve adjustment. From a cold start, if it is usually happy to start, but then runs poorly, we might rule out timing but not necessarily valve adjustment. But for the moment, let's put timing and valve adjustment aside.

You have been told it runs well and again, let's assume that's an accurate statement. I don't believe you have told us which condition your engine is in, starting-wise... but here are a few simple tests you might do before getting into all the more invasive stuff -

I conclude from your posts that your gut seems to be telling you you have a fuel supply issue, my first suggestion is to see if your engine likes to run better with a verifiably 'good' fuel supply. To do that, you're going to need a friend and a can of starting fluid. Here, you're going to eliminate most, but not all of the participation of your carb as a fuel supplier in this test.

Pull the air intake hose off the carb and with a friend trying to start the truck WITHOUT stepping on the accelerator, you give it some shots of starting fluid. Think safety. Do that at arm's length and from the side. Protect your face and eyes. Safety first. Some shots of starting fluid to start and some more to keep it going. Assuming it's going to start and run, do the starting fluid thing only for a moment. If it revs right up and runs strong with starting fluid you very likely have a fuel issue, n'est ce pas?

BUT, if it starts/runs with the starting fluid and still sounds weak and hesitant, stop there, put everything back together, Now start it and keep it choked a little. In doing so, you are enriching the air-fuel mixture by restricting airflow. Don't try to rev it up choked. That's not what we're looking for, the engine won't like it and higher RPMs really only mask problems. But, does it generally run better at idle while partially choked?

If it runs better partially choked, stop everything and start looking for a vacuum leak or an intake leak because that's probably what's causing your lean condition. For vacuum leaks, look especially hard at those out-of-sight areas such as the lines going to the distributor housing (particularly the one on the back side!). Those areas often get overlooked and you will find they often have very ratty hoses as a result. Those are very small hoses and they live in a hot environment and will degrade. They can crack and still look good so you are going to have to manipulate them a little bit and see if a crack opens up. Same with any of the other vacuum hoses. ALSO check to see if there's a decent rubber gasket on the distributor housing because if that housing is still hooked up to the vacuum line system the cap has to make a good seal.

NEVER EVER SPRAY ETHER OR ANY FLAMMABLE SUBSTANCE ON YOUR DISTRIBUTOR HOUSING!

IF YOU DO YOU MAY GET A BIG SURPRISE!


Raw air being drawn into the system anywhere after the air-fuel mixture point (carburetor) creates a lean condition. For intake leaks, it may be drawing air in at the gasket under the carb. There IS a gasket there under the carb, right? (Sometimes a guy will try to reuse a damaged gasket which causes a lot of headaches for the next guy.) It may even be drawing air where the intake manifold mates to the block. I'm not going to make any suggestions as to how you check that because even under the best conditions, the most efficient way of checking it is u-n-s-a-f-e and there is a risk of fire...but, if you take that route, do it only when the engine is not up to temperature, you've got proper PPE and a friend around to call 9-1-1.... and use something somewhat less volatile than ether.

So spend some time with your little truck and get back to us. We'll get you fixed up.

Cheers,
TJ

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Re: spark plugs

Unread post by tecknomage » May 17th, 2018, 3:50 pm

wow, thank you. I've tried some of what u suggested, well tear into her & get back...Again, many thanks sir.

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Re: spark plugs

Unread post by rickf » May 17th, 2018, 7:00 pm

It is VERY common for these engines to get vacuum leaks at the intake manifold. Most of the time it will be the underside of the manifold. This can be found by setting the hand throttle at a fast idle and then spraying carb cleaner around the manifold, be sure to get under the manifold. Also be sure to do this with the intake hose on and do NOT use ether. Either the hose off or any ether used at all will give a false signal from it being pulled into the air stream.

I also do not use ether for testing the fuel issue, I use carb cleaner. It will not cause detonation and also will not burn the hair off your head in a backfire.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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Re: spark plugs

Unread post by m3a1 » May 18th, 2018, 12:15 am

Sorry, Rick is right.

Right now we're just ruling stuff out so don't get disappointed if you don't find anything. We're doing the easy checks first. Still many other things to check but we'll nail your problem down do you can enjoy your truck.

Cheers,
TJ

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Re: spark plugs

Unread post by Vzike » May 18th, 2018, 8:55 am

This can be found by setting the hand throttle at a fast idle and then spraying carb cleaner around the manifold
Rick, we use a spray bottle with water. If there is a vacuum leak, the engine will lay down from a moderate idle.

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Re: spark plugs

Unread post by rickf » May 18th, 2018, 11:09 am

Vin, I have done that but if it is a small leak then there is a good chance that it will not pick it up. I prefer to use something that is flammable so that you are introducing fuel into a lean condition, that way the result is instant and recognizable even in the smallest leaks. Once you get a hit you can then spot check an narrow it down right to the spot of the leak. Plus with something like carb cleaner it clears up fast so that after a hit you only have to wait a couple seconds to follow up with the spot checks. Water will hang around and can run to different spots.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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