Info needed: Technical Assistance: M38A1-CND3

[RichCam]

I am helping a friend get his M38A1-CND3 (MFR SER#100202 Del 6-71) operating and I have 2 questions for the M38A1 experts:
1) the Engine Primer Pump - where does it pull the fuel from and where does it push it too? I can see the fuel tank line, in line fuel filter, fuel pump and steel line up to the carburetor but I don't see the primer pump hosing on the engine side of the firewall. I am trying to see if it is working correctly or not.
2) the Fording Control lever is not hooked up. Does it control a single wire or two wires into the engine compartment? I see 2 disconnected metal wires in metal jackets protruding through the firewall. Choke and throttle advance wires are working correctly.
We have ignition and proper battery voltage (24V) but I'm not getting fuel into the carburetor. New fuel tank was installed by the owner.
Thanks in advance for any advice.

[rob love]

Dole primer pump receives It's fuel from a T in the fuel line on the right side of the frame near the starter, and injects in into nozzles into the intake located on the carb side of the engine (one front and one back)head next to the carb. Usually this system is disconnected and the nozzles were not in the replacement engines, rather the holes would be capped.

Fording control cable controls two 90° valves, one at the PCV valve located near the fuel pump, and one between the intake air and the oil filler tube. These are most often found wired up, hopefully in the open position.

No fuel to the carb? Remove the line at the carb, add on a piece of rubber fuel line and suck. You are going to get the great taste of gas, but you will then know the potenti9al is there to draw fuel. Once you have your mouthful of gas, crank the engine and see if fuel is spurting from your freshly primed system.

There are other ways of doing it, but I'm giving you the quick and easy, albeit not tasty, method.

[RichCam]

Rob, thanks for the M38A1 advice. This jeep hasn't run in quite a while so I'm sure it is dry as a bone. Will post pictures and progress reports shortly.
Cheers, Richard

[rob love]

Forgot to mention, after you get that mouthful of gas, try and blow the fuel back down the line. If the fuel goes, then the checkvalves in the fuel pump are faulty. But if you try before you suck the fuel, they may well leak anyway as they do not seal so well after they have dried out.

[RichCam]

Thanks Rob for your advice. I was able to confirm that the carburetor is getting fuel from the fuel pump. The fine screen that is located just inside the carburetor fuel inlet was dirty so I cleaned it and re-installed. I was told that the carburetor had been serviced?????
Now, I am not getting ignition. I suspect that the plugs maybe fouled. I have not removed waterproof plugs before. Before I start wrenching things apart, is there a proper procedure or is there a need for a special tool?
The M38A1 didn't come with the service/maintenance manual or tool kit. All ideas welcome.
Regards, Richard

[David Dunlop]

Richard.

Nothing special about removal of waterproof plugs. Unscrew the wires from the top of the plugs with an appropriate sized wrench and then a standard spark plug socket can be used to remove the plugs.

David

[rob love]

The way David describes it is cporrect if ebeything was put together properly., Often it is not. The wires are supposed to be tightened finger tight until they wont turn with the fingers, then another 3/4 turn to seal them. However, often guys will wrench them right down. Then when you go to remove the wire, the whole plug will turn with the wire. To remove them at that point, you have to remove the wire at the distributer cap, then remove the wire and plug as a pair. Then you seperate them with a pair of wrenches.

At this point all you need to do is remove one wire at a plug, hold the wire about 1/8 of an inch from the engine block, turn on the ignition switch and crank the engine over to test for spark.

Coils, especially the new ones, are very susceptible to failure if someone leaves the ignition switch on for an hour or two. Seems the modern replacements will actually de-solder their tops off from the heat.

[RichCam]

I'm now past the BRAVADO stage of my life where I ignored my little voice to used to tell me "don't undue that" and I would end up with some spring loaded gizmo in a million pieces all over the workshop floor........or the left handed wheel nuts on the left side of a CMP.
According to my friend, the fuel tank was replaced because it had rusted and contaminated the fuel. Working from the gas tank forward, I suspect that the contaminated fuel might have fouled the plugs. If the plugs look fine, I will check for spark and correct ignition. Fuel, air and spark = combustion. Thanks Rob and Dave for your input, I'll get back to it on Monday. Cheers.
Note: Fording cables are disconnected and the intakes wired open. Dole primer pump is disconnected. Intake holes are not capped but piped together.

[rob love]

Quicker just to check for the spark in the first place, since you have to un-do the wires. The odds of having FOUR bad plugs is pretty bad. The Jeep should start and run on as little as two. My bet, if it's ignition, would be the coil.

If you have very weak spark, then points and condenser first. It is also possible to flash a wire to the neg size of the coil (with the wire to the points off) to achieve spark as a test for the coil.

[maple_leaf_eh]

Originally Posted by RichCam

...
According to my friend, the fuel tank was replaced because it had rusted and contaminated the fuel.
...

There are two styles of M38A1 CDN fuel tank. (Rob taught me this.) The two earlier contracts have sheet metal stamped tanks. The CDN3 has a much more robust welded flat plate tank. All will deteriorate! On my CDN3 the issue is the tank got punky and has been fibreglassed in place, hopefully to stop the rusting. However, the resin has stuck it into place, which makes it hard to remove.

[maple_leaf_eh]

Originally Posted by RichCam

...
The M38A1 didn't come with the service/maintenance manual or tool kit. All ideas welcome.
Regards, Richard

The basic tool kit in the Reserves circa 1976 to 1982 was:
bottle jack
jack handle with a joint in the middle
short tire wrench
long tire pressure gauge
maybe an 8" crescent wrench
maybe a straight blade screw driver
and very importantly, a SPOUT, FLEXIBLE ie horse c0ck for refuelling

All would be in a fold-top grubby canvas bag under the passenger's seat.

A conventional short handle round-nose shovel would be mounted under the hood. Always useful when the 17 or 18-yr old driver got it into a snowbank.

[rob love]

Originally Posted by maple_leaf_eh

There are two styles of M38A1 CDN fuel tank. (Rob taught me this.) The two earlier contracts have sheet metal stamped tanks. The CDN3 has a much more robust welded flat plate tank. All will deteriorate! On my CDN3 the issue is the tank got punky and has been fibreglassed in place, hopefully to stop the rusting. However, the resin has stuck it into place, which makes it hard to remove.

The flat metal, welded seam tanks are the replacement tanks. Made in Canada, they had filler necks that didn't accept the original gas caps very well. Underneath the tanks, in that deep well, was the perfect dirt and moisture trap. The tanks generally rusted from underneath. Reminds me that I need to remove mine, slean out the mudwell, and paint the well and bottom of the tank with something like tremclad or POR-15.

[RichCam]

Guys,

4 very dirty and soiled plugs came out of the cylinder head. Followed the procedure for removing the waterproof caps and I didn't have to remove the spark plug wires from the distributor cap. I re-installed after cleaning, squirted some gas into the air intake and it started, ran for about 3 seconds and quit. I repeated this about 4 times and each time it fired up, ran and quit. I suspect there is now an issue at the fuel bowl. So, does anyone have .pdf file or link for an exploded view of the Carter YS950S carburetor? Please post or PM when you have a moment. (Fuel pump is good, I have fuel up to the carburetor, fuel intake screen is clean)
Cheers, Richard.

[Wayne Hingley]

Hi Richard,
PM me with your email address and Ill send you a PDF of the Carter YS manual. The file size is too large to post here.

[RichCam]

Thanks Wayne, PM sent.

I will check out some of the other M38A threads as well.