John Deere H Timing

[Rholc]

I'm having fits with JD H. It spits, sputters, coughs and farts. Carburetor has been rebuilt.
To get the Impulse to fire at TDC, and have the magneto lugs horizontal, I had to skip two teeth from where the timing marks are.
I removed the cover on the engine and the camshaft/crank timing marks match up.

 

[Rholc]

Also, it seems that when the LH Exhaust valve starts to open, the mark is lightly past the mark on case. I assume the small indent is the correct mark.

 

[Rholc]

I have the impulse timing set between the 1st and 2nd mark, which I believe is correct for 6274.

 

[Rholc]

Is there supposed to be a "V" on the flywheel to match up to the "V" on the crank?

 

[JIM MN]

Find the V on the flywheel. If have to, take the paint off to see if the two V's line up..

 

[Rholc]

Jim - Do you think my flywheel is off one tooth? I stuck a camera down the spark plug hole and I could see the piston to find TDC. I put a black mark on the flywheel aligned with the mark on the cover. I am pretty confident in that mark.

 

[dan_41jdh]

Your flywheel is timed to the crankshaft correctly – the “V” on the crankshaft should point directly toward that threaded hole on the flywheel, and if you remove the paint on your flywheel, you’ll find the “V” on the flywheel aligned with that of the crankshaft. And in the second picture you are only a few degrees away from the LH EXHAUST OPEN markings and that might be because of cam wear, loose tappets, or other factors, but it proves the cam is timed properly to the crankshaft. And the impulse stop is set correctly for the 6274 drive cup.

However, what is very disturbing is the remarkable twist of the end of the exposed governor shaft. Those splines should be straight. That indicates that a Power Lift had locked up resulting in twisting that shaft. And this is just a guess, but such trauma might have sheared the key between the governor drive gear and the governor shaft. The governor drive gear is a press fit so it would grip the shaft even though the key may have sheared, but that might explain the reason why your magneto drive flange slots aren’t horizontal when they should be….

 

[Rholc]

Dan41 - I was curious about those splines. I thought maybe intentional to move oil out to the bearing.
I do not have hydraulics. I guess I need to pull the shaft and inspect. Thanks much for your input.

 

[dan_41jdh]

Dan41 - I was curious about those splines. I thought maybe intentional to move oil out to the bearing.
I do not have hydraulics. I guess I need to pull the shaft and inspect. Thanks much for your input.

Here's an exploded parts view of the pieces in question. If the key between the governor shaft and the governor drive gear had sheared and the governor drive gear rotated out of phase somewhat, that could be the reason your magneto drive flange slots aren't horizontal - but again, that's just a guess. But I agree, you should pull that unit apart and inspect for damage. The gears and the magneto drive flange are a press fit to the shaft and can be difficult to press off, but heating those items with a torch while pressing them off will help a lot.

 

[Rholc]

Thanks again. I'll let you know what I find!

 

[Mike(NEOhio)]

Dan41 - I was curious about those splines. I thought maybe intentional to move oil out to the bearing.
I do not have hydraulics. I guess I need to pull the shaft and inspect. Thanks much for your input.

Agreed, I found one like that at a flea market once. Didn't buy it of course. But that alone wouldn't affect the timing unless the key in the gear is sheared.

 

[Rholc]

So, does the fan shaft need to come off with the governor? Do I have to remove hood and fuel tank?

 

[dan_41jdh]

So, does the fan shaft need to come off with the governor? Do I have to remove hood and fuel tank?

Although it is possible, it would be better to remove the fan shaft assembly with the governor so that the fan gear adjustment can be made on the bench. And since you are going to disassemble the governor, the existing fan gear mesh will need to be adjusted, anyway.

The I&T manual says it can be removed as an assembly by removing the starter and generator (if equipped), exhaust pipe, breather (I think they mean the air cleaner and piping), fuel filter bowl, and magneto. The throttle linkage must also be removed, and I suggest removing the carburetor, also. By removing those items, the governor and fan shaft assembly can be removed without removing the hood and fuel tank assembly.

Personally, I prefer to remove the hood and tank assembly because that will give you much better access for governor removal and reinstallation and there’s less chance of scratching up paint (if that’s a concern). However, that does require removing the steering shaft, front grills, exhaust pipe and muffler, and the air breather and inlet pipe first. The instrument panel can be detached from the hood so the temperature gauge can be left attached to the coolant pipe so you don’t have to drain the radiator.

 

[Rholc]

It's off.

 

[Rholc]

 

[Rholc]

Both bearings need to be replaced.

 

[Rholc]

What else do I need to inspect?

 

[Rholc]

View attachment 66943What else do I need to inspect?

 

[Rholc]

There is a piece of metal broke where the guide pin goes.

 

[Rholc]

View attachment 66943What else do I need to inspect?