Engine wont run corectly ???? Help

I am having a problem with my stock engine running correctly . It will just barely idel and spits and spudders and backfires . I just put a fresh factory rebuilt carb on it with new points . Also drainded the gas tank and put new 91 octane in it . Also checked plug wires and no arking in the dark . Going to put platuim plugs in later tonight but i really dont think the plugs are the problem . I think it must be in the coil or timming . Going to order a timming light tonight to check the timming but dont think this is it either . Truck was running fine and slowly went down hill from there . The engine will ruff idel and when i give it just a little gas then it backfires and wont speed up any . I feel that im a fairly good mechanic but im realy scraching my head on this problem . Does any one have any ideals on this or maybe you have had this problem oh and when i leave the battery terminals on and dont disconnect the batteries the coil in the distribitor box gets real hot . Have to take battery terminals loose . Also engine keeps running when i turn the stock ignition switch off manually have to apply choke to kill engine from running i can use any help i can get

It sounds as though you do not have a stock, 24 volt system.

Do you have a 12 volt civilian distributor?

Are you sure the rebuilt carburetor is for the military 230 CID? There are a lot of 1920 Holley carburetors for various different engines.

Did the truck run OK and then start backfiring? Or did the problem happen after changing the carburetor and/or changing the points? Did you set the dwell or gap correctly on the points? (.020)

Knowing these few things will help to narrow down problems. These trucks are very unsophisticated in carburetion and ignition.

Backfiring coulde a lean mixture or incorrect timing... among other things. Hopefully we can get to the bottom of this issue! Good luck, stay in touch.

If you ;eave the coil energized for a long period of time and the points are in the right position...I think its when they are closed so juice flows through them...the coil will constantly be energized and dumping power...this WILL burn out the coil.

If I am wrong, it happens when there is a gap in the points but be assured, it does happen...been there.

Have you ever checked the timing? The stock 230 can run a lot of timing advance and still run well...if you are outside those parameters, maybe it could act this way...

Is it backfiring out the carb or the exhaust? I have always heard if its out the carb, its timing...if its out the exhaust, its fuel...

It sounds like you have multiple problems.

When you change more than one thing at a time it makes things more difficult to troubleshoot.

I'd take them one at a time.

The engine not turning off with the switch and the coil getting hot when the battery cables are connected lead me to believe you have a wiring problem. This may have contributed to the current problem by overheating the coil.

Have you pulled a spark plug and checked for spark? I'd start there. If you have spark what color is it? Is it a bright blue or a shade of yellow?

You say you drained the old fuel and added 91 octane. (If you have a stock engine 91 octane does not help. The engine will not run any better than with 87 octane.) Have you tested fuel delivery? The fuel (lift) pump on the engine uses vacuum to pull the fuel from the tank. If there is any problem in the fuel line from the tank to the pump you can have fuel delivery problems.

start with a compression check,with the over head cam could the belt have slipped cam timing.

I have had the engine diesel on shut-off due to a vacuum leak and timing problems.

Thanks everyone for your help ! I was able to fix the engine and it is running like a top . The whole thing started running slightly off and just kept getting worse over 4 months time to when it wouldnt run at all . So i rebuilt the carb and when i took it apart it was full of dirt and gunk so i thought that would fix it but no good it would just barely idle and would backfire if i tried to give it any gas . So i thought i rebuilt it and did something wrong so i bought a new factory rebuilt carb but still no good the same barely idle and backfire . Then i replaced the pionts because it was about 6 years since i put in a new set . Also let it set for about 3 years so i drained all the old gas and crud out . Checked the spark plug wires in the dark for any arcing and had none . So next i changed the plugs and that fixed the problem but the odd thing is i put a new set in it about 6 years ago and only put about 1,500 miles on them but some how they went bad . Dont know how or why . But im really glad i got it running . And as they say dont assume anything because i really didnt think it was the plugs but yes it was . So guys thanks for your help !!!

Points will corrode and not make good contact when they sit. Often, you can take a piece of 400 grit sandpaper, fold it over, drag it through the points and voila, fixed. But new ones are always a good thing for sure.

Good to hear everything is well now.

I'm replying to this thread because my 715 is behaving badly in the same way!
New distributor and coil with Pertronix ignition + wires + plugs; rebuilt carb; gas tank cleaned and reinstalled with 3 filters in line; supplemental fuel pump.
Yet she still coughs when trying to accelerate.
Timing is where it should be. Wondering if the timing chain is stretched but that doesn't show up with a timing light.
Working with a good mechanic when i can.

i'll try to diagnose for a vacuum leak and/or ohc belt slippage.
Input on how to do those would help!

Dave

About the stumbling when accelerating, do you have the original military carburetor, and is the accelerator pump squirting as it should? My truck came with the carburetor not attached. I rebuilt it but I determined that it was not an original military carburetor. It had an air cleaner wire hoop over the throat. And the jets had a different number. I got another one (military), rebuilt that one and all good.

Quote:

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Originally Posted by kwai

I have had the engine diesel on shut-off due to a vacuum leak and timing problems.

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Mine had a run-on problem yesterday, but after some thought I concluded ignition timing couldn't be at fault because the key was off. Key off = no spark.

IIRC, dieseling can be caused by too little octanage in the fuel, too rich an idle mixture or an idle that is set too high.

Advancing initial timing allows the engine to idle at a lower butterfly opening, reducing the chances of dieseling. You also get quite better throttle response.

Quote:

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Originally Posted by Mikel

IIRC, dieseling can be caused by too little octanage in the fuel, too rich an idle mixture or an idle that is set too high.

Advancing initial timing allows the engine to idle at a lower butterfly opening, reducing the chances of dieseling. You also get quite better throttle response.

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Exactly. Running after the switch is turned off is all of the above. Having the timing more advanced is often the culprit. But I have mine too far advanced, monitor it carefully but have a little more power. Not a recommendation, just "what I do". As Mom used to say, "Don't do as I do, do as I tell you!" (Or words to that effect)