Farmall H Issues

aerofarm

New User
I have a Farmall H that I hadn't run for several years. This summer I decided to get it out and do some mowing with it. The clutch was frozen, so i split it and replaced the clutch and all associated parts. It ran like a champ.

One day while mowing, it died. After it cooled down a bit, it restarted and went for a bit, and then died again. The next time it started it was running rough, backfiring, etc.

I assumed it was the carb. I bought a carb kit, took the carb entirely apart and cleaned and rebuilt it. Still no joy. I took it to a guy who does a lot of work on old tractors. He checked out the carb and said it was good. He found a couple valves were leaking pretty bad. I took the head to the head shop and had it re-done. Still no joy.

My magneto (Farmall brand) seemed to have a weak spark so I bought a new one. Still no luck. Mechanic thought the timing must be off, so he worked on getting the magneto timed to the engine. He claims the magneto timing and the engine top dead center never match like they should. Same with the old mag. He is pretty sure it is a broken gear in the hydraulic pump (I guess that connects to the mag???) Anyway, before we tear the engine down, is there anything else I need to be looking at. This was a great old tractor which is becoming a shed ornament.

Thanks,

Nate
 
Intake manifold gasket. You prably spent way
too much money on things it didn't need. It
prably didn't need a clutch, you could of
just rocked it in gear with clutch
depressed.
 

The clutch was bad - Rusted solid and was in pieces. Bearing was froze solid as well. I have not prob fixing the clutch. It's this engine running thing that's causing the grief.
 

Haven't tried a coil. That's on the list.

All the top end gaskets were changed when we re-did the head.
 
I have had an M and an A farmall both break a tooth (or teeth) off of the timing gears and behave how you describe. The only difference is, the A starting knocking from the front cover. The M never made the knocking noise, but it only had a tooth or two broken off and the A had at least 3 broken. Both tractors starting jumping time and popping out the exhaust etc.
 
If you can find a battery ign unit, it can be timed even if the gears are not right. I
have an odd magneto here that the impulse trips different than most too.
 
your problem is not the carb or it would not have ran that long. When it started backfiring that tells you timing is off not the carb
 
(quoted from post at 10:35:27 12/20/19) Are you saying you have a hydraulic pump between front of engine and the magneto?

I guess it's not the hydraulic pump. Its like an oil pump where you add oil to the engine. It comes off the front right side and the mag attaches to it. Is there something inside that that could mess out the timing.

It is not sparking when the engine is at TDC and we tried changing the position of the mag, checking the firing order, etc. All that is correct. But it is not sparking when it should. We are sure it's timing, but not sure where to fix it at this point.
 
Did you have the little gears apart that drive the rotor. They will change timing if not lined up correctly.
 
I agree you should check the coil since you said it has a weak spark, sometimes the coil works ok when cold but acts up when it gets hot. They are cheap enough or if you have another one off something else you can try to see if that solves the issue
 
If you have an aftermarket hydraulic pump that runs off the timing gears. The pumps were very hard on the timing gears. Sooner or later they would break gears or teeth.
 
Drain the oil & see if you can find any small pieces of steel chips. I think the front
timing gears are jumping time.
 
Gears are below where engine oil is added that drive the magneto. Are you using the first mark on the front pulley that gets to
pointer in normal engine rotation where the two notches are close together? If you remove the magneto you can see what position the
slots are the magneto slots go in. Can't remember the clock position now, should have it wrote down if I can find it. Problem could
be in the engine drive parts but I would guess not.
 
Why did you split it to replace the clutch?

You should be able to replace the clutch on an H from underneath with out splitting it.
 
Normal to replace clutch on H & M's through the bottom. Only split if flywheel removal is necessary.

I think he is timing to wrong mark, but if he is using correct mark, there is a problem with the gear. Loose nut causing shearing of half moon key in drive gear.
 
If it sat long enough to rust the clutch I bet the gas tank has rust in
it too. Better check fuel flow at the carburetor end of the gas line.
Should flow a full stream for several minutes.
Dave
 
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It seems to have a hydraulic pump of some kind between the mag and the engine.
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You have the much sought after M&W hydralic pump.the IH pump is much more common.The description you mentioned earlier points to a bad coil. The other issue may be it jumped timing due to a gear issus. Or you didn't get it timed right at first.retime. remove dist/mag. Roll engine over to TDC. use a screwdriver to find top' Remove valve cover to determine if it is right,or 180 out. Then set to approx. 5 degrees BTDC.Set rotor to it points exactly with the #1 tower of the cap. you should be timed.
 
Thanks so much for the helpful ideas. I haven't found as much info as I thought on the net. I'll change the coil over the weekend, and if that doesn't fix it, I'll tear into the timing again when I get back from the holidays. This is the best timing info I've gotten so far.

Thanks
 
I've taken an H and a 300 apart where the slotted drive "disk" that runs either the hydraulic pump (on the 300) or the distributor
(H) had severe wear to the half moon key and the keyway where it goes on the shaft. That sure monkeys with trying set the timing.

The 300 was the worst due to that part carrying the load of the hydraulic pump for a couple of decades.
 
Nothing to it on an H. I never tried an M. Super M disc can be changed but ain't easy for me anyway.
 
2 magnetos having the exact same problem, I don't think that would happen but anything is possible. Sounds more like a fuel problem to me, and now that someone else has been involved its so far out of whack you need to start over.
 
Try timeing it to Number one top dead center. Install a distributor. Mags can throw you for a loop if not familiar with them
 
I think Dave BN below may be onto something. I had a similar issue with a new to me Ferguson that had the fuel tank vent clogged. Rust or
other junk in the fuel tank is a real possibility.
 

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