Can't get my M38 to start

DFoley · Post by **DFoley** » Fri Jun 17, 2005 8:49 am

After about a week of not driving my M38 I took it out of the garage to go for a quick drive. She started up just like always, but then after about one minute she died. I did not think much of it until I could not get her to start again. After about an hour of trying various little fixes, I decided that something must be wrong with the carburetor. It is an original Carter YS model. It is basically brand new, just purchased from MidWest Mil. It probably has less than 100 miles through it. I took the top off the carb, and looking down through the body into the intake manifold I could see a puddle of gas. OK…so it is flooding out. I took the rest of the carburetor apart and inspected the float and needle valve. The float is fine but the valve was sticking very slightly. OK...so I cleaned the valve and while I was at it just about every over part on the carb. Put it all back together…tried to start it up…nothing, took the carb off again, still flooding the intake manifold. Took carb apart again clean every thing again, reinstalled carb, tried to start her up…nothing. And again the intake manifold had a puddle of gas visible. My question is how much gas should there be in the intake manifold? I suspect little to none, but maybe I don’t know what I am doing, and what I am seeing in normal. If the carb is flooding out, should I buy one of the refurbish kits since cleaning the one I have is not working? But anyway should this new carb I just got have lasted longer than ~100 miles? Is it possible I have some sort of sparking problem (i.e not getting a spark)? How can I check this? All other electrical appliances are working properly.

Additional info:
• I have tested the fuel pump and it is working properly with the appropriate pressure.
• I have taken out and inspected the plugs several times and thoroughly cleaned them during this whole process. They look fine.
• I have also tried several times (~12) to push start the jeep, to try to “work through” the possible flooding issue. No luck…she did not even try to start.

Post by **wesk** » Fri Jun 17, 2005 9:24 am

Remove the plugs and reattach them to their shielded military leads. Then crank the engine over and if they spark you need to do something with the carb. If they don't then I'll bet the next time you'll check for spark before spending a few hours disasembling carbs.

If no spark on any plugs open distributor cap and inspect. Check for 24 volts to coil + side.

DFoley · Post by **DFoley** » Sun Jun 19, 2005 5:13 pm

Ok...I pulled the #1 spark plug, reconnected it to the shield and cranked the motor and no spark. So it seems as though something is wrong with the distributer/coil. I dismanteled it and did not observe any obsious carbon deposits/charing etc. In any event I tried my best to clean all contacts. I reassembled the distributer and once again check for spark in the plugs. Still nothing. I guess my only option now is to replace the entire distributer. Any comments?

SteveJ · Post by **SteveJ** » Sun Jun 19, 2005 6:00 pm

Hi Dan

Distributors can be finicky. Just a hairline crack in a cap or rotor may cause the problem you are having. I would go for the easy stuff first. Points, condenser, rotor, cap, coil. If it was running OK then it is probably something simple. Check all the leads including the primary wire that goes to the distributor from the harness. TM 9-1825B is a good publication to help. also the TM 9-0812

I hope this helps.

Post by **wesk** » Sun Jun 19, 2005 6:36 pm

Dan,
Make sure the primary lead to the distributor is not shorting against it's metal shell where it screws on to the distributor by carefull inspection. Then make sure you have 24 volts to the pin while you still have it disconnected. With the lid off the distributor reconnect the primary lead plug and hold the points open or set them on the high point of a cam lobe. Turn ignition power on and check for 24 volts at the coil and some lessor figure at the lead to the points. Do you have the vent lines connected to the distributor?

OKCM38CDN · Post by **OKCM38CDN** » Sun Jun 19, 2005 9:06 pm

Sounds like either a coil gone BAD or like Wes suggested no 24v to the coil...

DFoley · Post by **DFoley** » Wed Jun 22, 2005 2:09 pm

Yes I do have the vent lines connected.

Ok this sounds like it is quickly getting beyond my skill level. What if I just purchased a completely new distributor/coil assembly from someone like MidWest Military? Wouldn't I then have to reset the timing? How hard is that? I don't think I can figure out exactly where my problem is in my current distributor, therefore is it reasonable for me to think I could reset the timing with a new distributor? Is any of this, something a local mechanic should be able to do? I have been very leery about taking this jeep to be fixed by someone who really knows nothing about them, specifically the 24v system or am I just too paranoid? I live in a small town and I have not heard of a really good mechanic in town.

I want to learn how to do these sorts of things myself, but I would feel much better if I had someone on hand who could help me out. Also I don’t have some of the special tools that are necessary, i.e. volt meter, and timing lights. I don’t mind purchasing what is necessary, but is this wise since I may not need then again for a very long while if ever.

Post by **wesk** » Wed Jun 22, 2005 11:10 pm

Dan,
I think if you check the price of a rebuilt or NOS distributor you'll start looking for a local mechanic in his 30's or older who works on old cars. If you have the TM 9-8012, TM 9-1804A and TM 9-1825B (1954 or newer) he should be able to solve your dillema. A set of military electrical test adaptors would also help. You can buy them for $30 to $50 dollars.

DFoley · Post by **DFoley** » Fri Jun 24, 2005 9:28 am

Ok...I think I have figured out were the problem is. I purchased a volt meter and measured the voltage going into the coil...~23V. But the voltage coming out of the coil was ~3V. So it appears as though the coil is bad. I just ordered a replacement coil plus a few other distributor parts (as a back up). I will let y'all know how it goes when I get the parts installed in a few days.

DFoley · Post by **DFoley** » Thu Jul 07, 2005 9:44 am

OK...I have done a fairly thorough overhaul of my distributor. New distributor cover and new cap, new coil, new points, new condenser, and new rotor. Once all this was installed she started right up, just like before. This minimal overhaul was actually very easy. As I replaced several parts at the same time, I don't know which of these parts was actually causing the original problem, but I am pretty suspicious of the coil. Thanks for all y'alls help.

Post by **wesk** » Fri Jul 08, 2005 10:54 am

Did you plumb the distributor vent system back in place?