M37 Still Won’t Start – Not Sure What To Look At Next

[bubba_got_you]

True about the civilian oil pump. I don't know what his aftermarket distribnutor uses for a block attachment.

There are a couple of pins along the distributor shaft and oil pump drive in the military set up. I don't know what the aftermarket distributor looks like, but if any of those pins sheared, the rotor might spin from shaft drag, but not stay in time.

This is a tough one. Hard to diagnose without having my hands on it.

it would be good to check those pins first. id pull the cover and see if i could spin it with my hand.

 

[Oldfart]

Regarding the timing - even if it's way off - shouldn't I get some indication the engine is trying to start. I don't get anything at all that makes me think that any of the fuel is igniting. When I try to start the engine the sound and feeling I get would be the same thing you'd get if you tried to sart the engine with the ignition in the "OFF" position.

Yes, usually there is some indication of an attempt to fire. Backfire through the carb or popping out the exhaust. Still, you have gas at the carb, have drained gas at the carb and have put ether and perhaps gas in the throat of the carb. Given the air flow you have determined through the engine there should be enough to fire something. ~~~~ Very puzzling, but in the end it has to be a fuel or ignition problem.

 

[Capt.Marion]

Take a picture of your distributor, distributor shaft, and your oil pump.... (and your engine bay in general, too). This might clear up some of the confusion.

 

[bubba_got_you]

Take a picture of your distributor, distributor shaft, and your oil pump.... (and your engine bay in general, too). This might clear up some of the confusion.

good idea

 

[glcaines]

Are you absolutely positive you hve the ignition wires hooked up correctly and not in the proper sequence?

 

[IGALL1]

Carb or ignitor or compression or timing........

Here's what I gathered from working on my old "hard-headed" flathead for the past ten years. When the thing dies like you turned it off while your ten miles from your shop and its about to rain, it's the coil. The stock military carb for the 230 is a finicky old dog! Everything has to be spot-on for the thing to run. For example, at one time, I had known carb issues and rebuilt the sucker a couple of times. That didn't work so I ordered one from M. E. Then that one didn't work so I sent it back and got another one. It performed perfectly! Then I've heard of the old governor under the carb giving people problems (never mine). Now for the ignitor. I was thinking I'd get rid of those pesky points and modernize the distributer with the MV-161 like you have. Well I put the first one on and smoked it when I turned on the ignition somehow, put the replacement on and didn't smoke it, but never got it to fire. So I said 'to **** with it' and put new points back in and it ran great. Real fun stuff to be messing with that stock military distributer so much....... Next the compression. I had different and bad compression in all cylinders like you did. Now that motor is beast enough to run on two cylinders when everything else is right, as mine did that very thing. But the compression is crucial. The book is right about the range of psi. I swapped my block with a rebuilt long block from M. E. Then the timing. I found TDC of #1 and made sure my rotor was pointing to the right wire and hooked up my timing light and pointed it at the crankshaft pully where timing marks were present. It timed perfectly. The 230 is one heck of a boat anchor, but don't give up. Once you get her right, she'll never let you down.

 

[majorhitt]

I had the same issue more or less, Tried all of the suggestions that were in the previous post. I did check the plug wires to verify wire from post one went to plug one and so on. Have you tried this? remove the no 1 plug and the cap from the distributor then Crank the motor and watched the rotor to see if the no. 1 cylinder had compression when the rotor was at the no location. Then replaced the cap and place the plug so you can see the electrode (the plug should be on the motor and making contact with metal) . Again crank the motor to see if you have spark and ( place your thumb over the no. cyl hole for compression check) compression at the same time.If you feel the compression and see the spark you now know if your timing is somewhere in the ballpark. After doing all that was previously mentioned and then some, My M37 still didn't want to start. I thought the batteries were full charged also. A friend that was helping me said let's push it. At this point I was all for it but the river was too far away. We pulled it out of the garage and pointed it down hill and gave it a push, I didn't go more than ten feet and it was running!! Now it starts all the time!

 

[Oldfart]

Another possibility is the rotor gap between the distributor cap electrodes and the rotor. If that gets to large, it gets hard for the spark to jump from the rotor to the plug wires. An improvement in spark might have overcome that for a bit. Worn distributor shaft bearings will usually cause erratic performance, not a no start.

 

[glcaines]

Any progress?

 

[F18hornetM]

Read through most of the notes here, and thought I'd add my 2 cents worth.
If I read this right, you replaced the distributor with an electronic one?? And that was before this "no-start" problem? it was for a slugish and performance problem. I saw a few guys mentioned a bad coil, when it heats up, thats true, but I have also seen modules heat up and do the same thing. Im sure if its an electronic distributor it has a module. Did you try the old distributor back in it?? might be sluggish, but it may help u narrow down the issue
I know nothing about a M37, so, what im suggesting would apply to anything with an engine, [Its my trade] as far as wondering if fuel is gettng to the engine, you can isolate that easy, by using [as I cringe] ether or WD40, not sure if these are up draft or down draft carbs, if down draft, just put some fuel down it, [be careful] if still no start, its not a fuel problem..gotta elimnate some things, But after reading all this I am suspicious of the electronic module...if it has one!! lol
sometimes we tend to overthink things, do the basics...Fire, fuel, air, compression..[doubt its compression if it ran before, and that wouldnt cause it to just quit all together] . Didnt notice in the posts if it was checked for Fire at the plugs, use a spark plug tester, or screwdriver. If you have fire then its not a matter of the dist, being turned,,,may not be in right time, but its turning, try to not work on all the functiosn at the same time, pick one area, fire/fuel etc, and eliminate that as an issue,
not sure if anything i said helps, but good luck

 

[sktww]

i have ben reading this thread carefully because i seem to be having the same prob. how does one ck the coil to see if it really works?

 

[citizensoldier]

Let me first say I skimmed through all the posts so this might have been covered. It sounds to me like your first issue with it running and then dying was a bad coil. Now after changing things maybe you have created a timing issue somehow. If you get all your timing figured out and are certain its right. It then sounds to me like a vacuum issue. Going by your compression #s that seem low your probably not creating enough vacuum for it to run. This could have also contributed to a vapor lock when the engine gets hot along with the fuel line being to close to the manifold. You should have a head sheild above the fuel pump to prevent this. Do you?. Might be time for a valve job and lifter adjustment. I say this because you mentioned sluggish performance. I know, I know another You might need to pull start it to get it to fire off the starter on these old dogs just don't have the RPMs and balls to blow out a candle much less light one.

 

[IGALL1]

To check a coil yoou must use a multimeter, or Ohm meter, and check the resistance. As far as how many ohms that coil is supposed to have, i'm not sure. If you can find out how many ohms of resistance that coil is supposed to have, you can then accurately check it or 'ohm it out'.

 

[trucknut]

I commend you on your perseverance. I had a heck of a time getting my chev 350 to run right. I set the timing up and it would not start or run and than die. We finally figured it out as slack in the timing chain. Perhaps this is your problem.

 

[Milbikes]

I had a little Crosley that sounded just like this. It turned out that the wire for the condenser was shorting to the distributor body. Although you have spark, so that may not be the case.

I had a 1959 Apache panel truck that I rebuilt the motor on when I was in high school. I couldn't get it to start,....for about six months. It turns out I was trying to time it to the wrong cylinder. What I thought was number one was number six, or it was supposed to be timed to six instead of one....something like that. To me this really sounds like a timing issue or a really bad intake air leak..... but if you have used ether, and there was spark at the correct time, you should have had some running, popping etc.

Be REALLY careful with ether. You can have a flash fire in a heartbeat, and it can really get away from you quick. Also, ether is really harsh on an engine (knocking), and it washes the oil off the cylinder walls, and can cause damage. I tend to avoid it. If I do use it, I use one or two quick shots at most, and if that doesn't get the ball rolling, I stop using it and look for the root cause of the problem.

 

[joseph m37]

After months of work I still can’t get my M37 to start and could use some advice.

Prior to doing all this work the vehicle ran but would just quit after 15-30 minutes. (usually at a very inopportune time).
Here’s the parts I’ve changed so far:
1) Gas tank had rust – so removed and had it completely restored
2) Changed the fuel lines as a precaution
3) New Fuel Pump
4) New in-line Fuel Filter
5) New distributor
6) New spark plugs
7) New spark plug cables
New carburetor

So at this point, I know for certain I have fresh clean fuel at the carburetor (I can see it in my in-line glass fuel filter) , I have verified I have high voltage coming from each of the spark plug wires (spark jumps about ¾ of an inch without issue). I thought I may have installed the new distributor backwards to I took it out and rotated the shaft 180 degrees, no change. I guess I am now suspicious that my new carburetor may be at issue – I just don’t know what else it could be. I have a couple of small backfires – not sure if that is any indication of the issue. How can I verify I have a good air/fuel mix making into the cylinders?

ok mumber one,disconnect the fuel line from the carb see if fuel is coming to the carb,2, remove the smal drain plug on the bottom of the carb to see if the fuel bowl has fuel, it should pour out if theres fuel,# if not shout off your fuel valve going to the fuel pump disconnect the fuel line from the carb, remove the needle valve inside the carb where the fuel line connects,check the valve for debris,should be absolutely clean,if so measure the distance to the float through the fitting hole where you took the needle valve from and compare it to the lenght of the needle valve you may have to add another rubber washer inside your issue sounds like no gas

 

[joseph m37]

After months of work I still can’t get my M37 to start and could use some advice.

Prior to doing all this work the vehicle ran but would just quit after 15-30 minutes. (usually at a very inopportune time).
Here’s the parts I’ve changed so far:
1) Gas tank had rust – so removed and had it completely restored
2) Changed the fuel lines as a precaution
3) New Fuel Pump
4) New in-line Fuel Filter
5) New distributor
6) New spark plugs
7) New spark plug cables
New carburetor

So at this point, I know for certain I have fresh clean fuel at the carburetor (I can see it in my in-line glass fuel filter) , I have verified I have high voltage coming from each of the spark plug wires (spark jumps about ¾ of an inch without issue). I thought I may have installed the new distributor backwards to I took it out and rotated the shaft 180 degrees, no change. I guess I am now suspicious that my new carburetor may be at issue – I just don’t know what else it could be. I have a couple of small backfires – not sure if that is any indication of the issue. How can I verify I have a good air/fuel mix making into the cylinders?

 

[joseph m37]

After months of work I still can’t get my M37 to start and could use some advice.

Prior to doing all this work the vehicle ran but would just quit after 15-30 minutes. (usually at a very inopportune time).
Here’s the parts I’ve changed so far:
1) Gas tank had rust – so removed and had it completely restored
2) Changed the fuel lines as a precaution
3) New Fuel Pump
4) New in-line Fuel Filter
5) New distributor
6) New spark plugs
7) New spark plug cables
New carburetor

So at this point, I know for certain I have fresh clean fuel at the carburetor (I can see it in my in-line glass fuel filter) , I have verified I have high voltage coming from each of the spark plug wires (spark jumps about ¾ of an inch without issue). I thought I may have installed the new distributor backwards to I took it out and rotated the shaft 180 degrees, no change. I guess I am now suspicious that my new carburetor may be at issue – I just don’t know what else it could be. I have a couple of small backfires – not sure if that is any indication of the issue. How can I verify I have a good air/fuel mix making into the cylinders?

if a vehicle runs for 20-30 minutes then shuts off, with no starving for gas then its electrical, my guess is you coil needs to get replaced,at some point your coil overheated and the secondary windiings are seperating inside the coil cutting off the current,put a new coil in, make sure the vent lines are connected to the distributor housing also they are there to help cool the c oil because its in a waterproof housing

 

[joseph m37]

if a vehicle runs for 20-30 minutes then shuts off, with no starving for gas then its electrical, my guess is you coil needs to get replaced,at some point your coil overheated and the secondary windiings are seperating inside the coil cutting off the current,put a new coil in, make sure the vent lines are connected to the distributor housing also they are there to help cool the c oil because its in a waterproof housing

also on military vehicles,the on-off switch must be turned off when not running the vehicle, if left on you are energizing the coil and after time it will heat up and seperate the windings inside the coil,causing a vehicle to run and then when the coil gets hot seperate and no current! a lot of times its diagnosed as vapor lock but its not

 

[plym49]

If you are still having the issue, try reversing the primary connections on the coil. If backwards, the coil will not provide enough spark to fire under compression even though you see a spark in open air. Because the coil is an autotransformer - they are hooked up the same regardless of whether a vehicle is positive or negative ground.