Troubleshooting '47 M - No fuel in cylinders?

Ken Christopherson

Well-known Member
Headed back over to troubleshoot the 1947 Farmall M in the morning. I'm hoping to have it running tomorrow. For those who missed it, I seem to be having an issue getting fuel from the carb to the cylinders. Here is a brief overview of where I am at:

Valves: Set at .018, cold. (calls for .017 hot).
Mag impulse: set to fire #1 as the first of the two 'double notches' on the crank pulley passes the timing needle on the front timing cover. Plug wires set up as 1-3-4-2 in a clockwise rotation (looking at the back of the rotor). Checked for spark - hot purple/blue spark. Spark plugs gap set at .025.
Carburetor: Idle mixture screw adjusted to 1 1/2 turns out. Load mixture screw adjusted to 2 3/4 turns out (factory recommended settings).
Cam and crank timing: single punch mark on cam lined up with single punch mark on crank - #1 cylinder at TDC.
Cam and magneto drive timing: double punch mark on cam lined up with double punch marks on magneto drive.

Even with full choke (no matter the throttle position), I seem to not be getting fuel past the carburetor. I know I've got good flow, I removed the line and got a steady stream. The carburetor does flood out and drain out the intake after a few cranks on full choke (so I know there is plenty of gas). I pulled the spark plugs, and they are dry as a bone, and have no smell of gas. I didn't try to pull start it but I cannot fathom why I'm not getting gas from the carburetor to the cylinders. I did spray some carburetor cleaner into the carb intake to see if I could get fire that way and I did get one loud "bang" out of the exhaust.

I've watched my timing videos a few times now (Episodes 13 and 14), and after paying close attention I can only come to the conclusion that the crank, cam, and magneto drive are set correctly. In the morning, I will start with putting a few squirts of oil into each cylinder. I will then double check my valves and make sure they are adjusted properly. From there I will move to the magneto impulse - making sure it fires just as the first of the double notches passes the pointer on the front timing cover. After that I will double check the spark plug gap to ensure it is set correctly. From there, I will install the (NEW) 12v battery and crank it to ensure I have good draw through the carb. If all checks out I will then pour some fuel in the cylinders to see if I can get it to fire. I really cannot think of anything else to try. Hopefully by then my friend will be off work and may be willing to assist me in pull-starting the tractor if I can't get some fire out of it. I'll be video-documenting the process so that everyone may offer suggestions should it not work. I am hoping to have it running tomorrow, though!
 
Crank it over with hand crank, should suck hard on your hand if you hold it over intake of carburetor.

Bottom line, make sure it has compression and vacuum will be indicator of that.
 
I don't have a hand crank, but have been cranking it over by hand with the use of a pipe wrench (please forgive me). It definitely has a lot of compression, as it takes a lot of effort to pull it through the compression strokes. I haven't been able to test the suction through the carb yet, but I will in the morning.
 
remove #1 plug wire it up and make sure its grounded then with your finger in the hole when it turns over you should see spark when compression pushes your finger. You could remove all the plugs and squirt some gas in the cycl then you should get it to fire.
 
do what Gene says only do it on the rear plug closest to the starter button that way you can check it by yourself using the starter.
 
You seem to have covered all bases.
Is there a chance there might be a wad of packing lodged in the intake venturi that you missed?
Could there be a bugger or something lodged in the main jet tube that was missed?.
Not trying to insult your process of trouble shooting but stuff like this humbled me at times.
If everything is set right it should be able to start with a hand crank on the first pull after the choke pull.
 
1) I don't recall seeing any packing inside the manifold (it was a brand-new manifold that was in a sealed bag, inside a box). While painting it I got a lot of views from many angles, and don't recall seeing any packing.

2) The carb was soaked for approximately 2 days in a gallon of carburetor cleaner prior to the rebuild. All new internal parts were used.

3) Seems as though it should run, seeing as nearly everything inside the motor is new.

4) I have been humbled before as well. On my 1941 Case SC I misadjusted the valves after a rebuild. Could not get any power out of it until I went back in and double checked the valves - but at least it ran. That is what is throwing me for a loop.
 
This is what I will attempt to do after checking things over. I've got a brand new clean spray bottle to fill with gas so that I can squirt gas into the cylinders prior to the attempts.
 
Okay I should probably do some research on this before I post but just shooting from the hip. If you were wrong in setting the timing as stated I would think someone else would have piped up. But wouldn't the first notch in the crank pulley be "before top dead center" (BTC)? So piston is still coming up. This is were the lack of research comes in, because I'm not sure what is designated by the pulley notches. To my thinking that the first notch would be the advanced position the mag advances to when running. All this really does not explain why it will not run because I think it would still start just may kick back on the starter. All this means nothing if you indeed have the timing set correct. I would also say don't be afraid to get some gas dripping out of the carb from choking it. Realizing that starting a fresh overhaul on a rich mixture is not ideal, but your dry plugs are not supporting a rich mixture. If you are still having problems I'll open up my email and I am open to being contacted. If you so choose I might be able to swing up and take a look, I live in Coon Rapids.
 
According to the manual, it is to be set to the first of the double notches. Just got done going through the valve to piston timing and readjusting the valves. That's all good. Next is to check carb vacuum. I'm up in east bethel, if you're bored. Feel free to contact me, email is open.
 
How about the tang in the govenor shaft? Are you positive it is I the notch of the throttle shaft of the carb? Did you double check everything was moving under the angled plate above the govenor with the vent tube on it? Just throwing stuff out there!
 
Red,

I did double-triple check all of it. You guys aren't going to believe what it was when I get done with this video... Ahh heck, I'll just tell ya now.

I had the plug wires out of order! I couldn't believe it. Absolutely baffled me. I thought for SURE I had them right! I guess Southern Ray was right.. I've been humbled once again.

As of now the tractor seems to run good, but not great. There seems to be a slight miss (I'm guessing because of the characteristic rain-cap bouncing), and after getting it good and warm after a trip down the road in road gear, it has a 'hiss-hiss-hiss-hiss' noise coming from what sounds like the exhaust on a particular stroke of each cylinder. I thought it might be an intake leak so I sprayed carburetor cleaner all around the manifold near the intake ports, and nothing seems to be leaking there.

Maybe I need to fine tune the valves now that I got it hot? Stay tuned for the Grand Finale video!
a230680.jpg
 
(quoted from post at 15:38:49 06/28/16) Red,

I did double-triple check all of it. You guys aren't going to believe what it was when I get done with this video... Ahh heck, I'll just tell ya now.

I had the plug wires out of order! I couldn't believe it. Absolutely baffled me. I thought for SURE I had them right! I guess Southern Ray was right.. I've been humbled once again.

As of now the tractor seems to run good, but not great. There seems to be a slight miss (I'm guessing because of the characteristic rain-cap bouncing), and after getting it good and warm after a trip down the road in road gear, it has a 'hiss-hiss-hiss-hiss' noise coming from what sounds like the exhaust on a particular stroke of each cylinder. I thought it might be an intake leak so I sprayed carburetor cleaner all around the manifold near the intake ports, and nothing seems to be leaking there.

Maybe I need to fine tune the valves now that I got it hot? Stay tuned for the Grand Finale video!
a230680.jpg

Hot to international is above 32° so run them after you re-torque the head.
 
Time to re-torque...yes...re-torque the head. THEN set the valves in firing order sequence after you warm it back up. You will need to remove each plug in firing order ( 1-3-4-2) and use a plastic spray tip off of a wd 40 can. Insert the tip, hand crank the engine over using the fan ( in correct running rotation ) when the piston just gets to top dead center, adjust both valves on that cylinder only. Move to the next cylinder in the firing order, repeat. If you happen to feel the piston start down, back it up a half turn & go in correct rotation to bring it back to top dead center using the red tip to "feel" when the piston rises.
May sound a bit complicated, but you will get the hang of it pretty quickly.
Hissing noise should dis-appear, and should really purr at idle.
Ignore the rain cap "banging" until you get the motor broke in by running at half to 3/4 idle for around 3 hours. Check the gauges & for leaks frequently. Verify head & radiator temp with hand held thermo.
 
I figured that was the case. I knew the expansion and contraction of all of the new components in the head would probably cause some valve leakage again. Good tip with the plastic straw in the spark plug holes.

So far, I have zero leaks due to gaskets, oil, or tubing connections (which is pretty awesome). It felt really good to get back on an M that was moving under it's own power!

Thank you all for all of your help!
 
I'm glad you got it running.
I spent the rest of the afternoon drying out my shorts when mine started.
My big problem on my M was I could not get the mag to strike on the double lines.
Finally found whoever last worked on the mag did not reassemble the mating flange right side up.
There was no way to adjust the timing.
Had to pull the mag apart and completely rebuild it.

Enjoy that tractor. You did a nice job.
 
Thanks Ray!

I think, actually, when I pulled mine back apart today, when I pulled the plate off to inspect the two rotor gears I actually caused the gear to rotate and get out of time a little, but since I was double checking it anyhow, it was fixed immediately. I couldn't believe I had the spark plug wires out of order. It took me even a couple combinations before I even got it right. Just goes to show you - sometimes you complicate things by overthinking it. At least it worked out where I was right on everything else (except maybe initial cold valve clearance being set to .018"). I reset that to .020" due to others recommendations and it is probably good I did because after a good warm up I am getting that hissing sound. I'll get around to a retorque on Friday and then run it and reset the valves warm at .017" per the manual. Then I'll put some diesel in the rear end and run it around a while to really flush it out and refill with new fluid.

Just happy to have it running, and thanks again for all the help from everyone.
 

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