Dodge Military 6 cyl flathead help won't start

My fire department has a 1953 M37 Military Dodge power wagon with a flathead 6 that we use for a brush truck. It quit running the other day and had very weak fire. We replaced the coil, points , condensor and now have plenty of fire at the plugs however it still will not run. Even took the plugs out one at a time and watched them fire. Compression on all cylinders cold is 72- 75 ft lb. If we turn it over several times with the ignition off the rear 2 plugs are wet with fuel but the front 4 are dry as a bone. Even if we dump fuel or spray starting fluid down the carb throat it still does not even attempt to fire up. Does not seem to have any vacumn leaks on the intake side as we have removed the vac lines and plugged them, there was only 1 for the wipers. Has plenty of fuel from the fuel pump to the carb. If I remove the PVC valve fuel runs out of line when cranking over, pluged the line and still doesn't fire up. Any suggestions?
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plugged exhaust. damn mice!

 

Don't think so it was getting ran everyday

 

Did you change plugs too and does every plug fire? Check each plug gap. Valve guides could be gummed up, slow to close so compression getting past when plug fires. Could still be lack of fuel, you could try a squirt in each plug hole instead of down the carb. Hope this helps.

 

This may sound crazy, but is it sitting on level ground?

 

Plugs all fire great. Some fuel in each cyl makes it try to fire for a second maybe. All kinds of fuel at the intake below the carb as I said. This old girl has been good to us for many years without any major issues. This one has us all stumped. Most of the local mechanics are way younger than she is so they aren't interested in even taking a look...when you say flathead they just look puzzled! Thanks for your suggestions. I tend to agree with you it may be something in the valve train.

 

Yep setting inside a warm fire station

 

If there are no intake leaks (loss of suction to those cylinders) I think the valve train may be the right place to look.

 

I agree, just didn't want to tear into the guts unless it was necessary. Thanks

 

Well, any gasoline engine takes
Fuel/air mixture
Ignition=spark
Compression

together At the right time
To run.

It looks like you have the spark and what should be enough compression to run. The fuel mix may be off but it should at least try to fire.

Is the engine in time? If you pull #1 plug and crank it over to get it up on compression and the marks lined up is the rotor pointing at #1 on the cap with the cam just opening the points?

 

You have a PCV valve on a '53 dodge flatty and when you remove it and crank fuel runs out of it?

What do you have the pcv valve hooked up to? I can't believe that you have that much fuel in your crank case and can't figure out why it won't run?

If you are talking about running back out of the intake then you have it flooded all to hell.

You are talking about the front plugs being dry and the rears being wet it sounds like you arte not getting any mix into the front cylinders while the rears are flooded. You might check and make sure the front valves are comming open.

Getting back to the fuel running out of the PCV if you have that much fuel in the crank case it sounds to me like maybe you have a very serious problem. Who drove it last talk to them about what it did just prior to comming apart.

 

It sounds like a leak in the gasket between the head and the intake manifold. Try installing a new gasket and see what happens. I worked on those when they were new for the original owner. How many HAMBers can say that? I might still be wrong but give it a shot.

 

First I am ASSUMING ( I know thats a mistake) that the valve I am talking about is a PVC valve. It runs from the intake below the carb back to the block via some 1/4 piping and elbows which is original according to the manual. Yes fuel runs out of the line if I unhook it. The truck began running rough while driving it and then just quit! In regards to being flooded that was my first thought originally but after removing everything and cleaning up the plugs etc. it still wouldn't fire up so thats when we began looking deeper. Still one would think ALL cylinders would have wet plugs since I have that much fuel in the intake.

 

Change "head" to block. Been working on Chevrolets too long.

 

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Seems if it were a stuck float ALL cylinders would be wet..not just 2?

 

Not necessarily, I've had more than one engine both V and inline that have only flooded certain cylinders and not others.

If you can pull the vacuum line off the engine and gas runs out, it is flooded and you will have to figure out why.

 

Did you dick with the wires??? Is it possible the wire are a tower off on the dist cap.

Pull the plugs crank the engine with your thumb over number one plug hole, when you start to feel pressure pushing your thumb stop cranking. then rotate the engine with the fan till the timing pointer is as TDC on the crank pully. This will put number 1 at tdc. Assure the rotor is pointing to the correct plug tower on the cap and that the wires are correct for the firing order.

When I put mine back together after a rebuild It displayed the same symtoms, and after checking the firing order twice, I finally rechecked the rotor alignment and was off by one. Getting it corrected it started right up.

75 lbs of compressioin is a bit low, should be in the 90 to 100 range, but consistancy across the cylinders is the important thing.

 

Never had the plug wires out of the distributor. On the military version the cap goes inside another cap that the wires are fastened to.

 

they flood out
they have a governer
shitcan the milspec dist
rotors on mopar short out through shaft
get rid of all the millitary standard and put civilian carb et on, they have too much fuel pressure and flood out or pressure regulator

I had one of thes jewels in Nam and it run 85 mph before it exploded and they removed it from my possession, so I know what causes them to die on the road not fun in Nam

 

When I was a MoPool Mechanic I was always fooling with the Ball and Ball carburetors on those things. See if it's flooded. Ours were a lot of the time. I always wanted to put a Rochester mono jet on one of those things to see if it wouldn't run better. But you know how those Army guys are. Have you sheared off the roll pin in the shifter top stick yet? That was the other thing that happens to them. We cranked a bunch of toe in into ours to make it steer like power steering. Tires were free. Then the chaplains assistant rolled it one day. Bummer. Ours had custom Air Force canvas on it. And a good heater. Before it got rolled.

 

sure sounds like the fuel isn't getting drawn into the cylinders. the rear two are wet because of gravity. did the truck drive through a puddle? had this happen on a cadillac once the exhaust crushed on the inside.

 

PCV valve should will look like this Mil-Spec photo.

 

You have compression, gasoline , and spark, and it runs when you spray into the plug holes..
So, you know that everything is ok with the valves and timing, But, you don't know that the gasoline is getting distributed to the cylinders, except the rear two are wet.

Ok, the carb is flowing through the accelerator pump , which get s the gas on the floor of the manifold. But , it is probable that the main, and idling, jets are blocked and the mixture is not being fed into the cylinders.

Clean the carb and try again.

Traderjack

 

Did you check to see if it is timed off #1 or #6?

Timing procedure for a dodge flat six
Pull the pipe plug out of the head on the #6 hole.
Put a wire down the hole and turn the engine over with a bar untill the piston is on TDC at #6 cyl.
Pull the cap off the dist. Attach a test light from the points to ground. Turn the dist untill the light goes out. Re install cap ensure that rotor is lined up with #6 plug wire.

I had a 54 dodge M37 canadian truck with a 251 in it. They have the advance coming on at starting Rpm so they are a little odd to time properly. A manual choke carb off a ford 300 6cyl might be a huge improvement. I used two rochester 1bbl off of ford 170 six cyl on a dual manifold, it made a huge difference in driveability.

 

Thanks for all the help and suggestions going to try some of them today. Think we will start with the carb and work from there. Anyone else has any ideas keep em coming when she runs I'll let you know the problem. Thanks again!

 

Better check the oil level before you try starting it, flooding that bad can put quite a bit of gas in the pan. You might get a pan explosion when it fires up, that can blow the pan right off. Not fun!
Those old Ball and Ball carbs worked OK when new, but that was half a century ago. A 300 Ford six Holley as mentioned above is a good choice.
Could be the timing chain jumped a cog or two. If the distributor timing is off, without you moving it, that's a good indicator that it's slipped.

 

Got her runnin! The float needle valve was stuck open! Thanks guys for all the advice. Changed the oil which had a bunch of gas in the pan, cleaned everything out and she purrs like a kitten and starts great! One thing I learned you do not need to remove the carb to cleanup the float needle valve, its right in the fuel line fitting at the carb. I found this out after removing the carb of course, but it allowed me to clean everything up and learn how a down draft carb works! Worth the effort for the education! Again thanks for all the help!

 

ya might want to put some fuel injector cleaner in an empty tank, then fill'r up full, just to attack any gum in the fuel lines. Also put some of that Marvel Mystery Oil in the crankcase to get any gum in the valve guides.

 

Put in new plugs, they may fire when out of engine but will not fire under compression. Iceman