John Deere H Hard Starting

[Indiana George]

I have a a 1940 John Deere H. I am having a lot of problems hand starting it, and i can only get is started by pulling it. When I have checked the spark on the magneto, the spark color is blue so I know it has a good strong spark. I have also replaced the spark plugs. When i do pull start and get it going it is back firing like crazy. I timed the tractor by the book, So I am assuming it is timed correctly. Anyone have any ideas? is it not timed correctly? Thanks any input is appreciated cause i am stuck!!
 

[J.Wondergem]

Are you sure the choke is working?
 

[AnthonyU]

Sounds like your mag is weak anytime I have had to pull start the tractor the mag was weak or needed a rebuild. Try cleaning your points in your mag first the next thing I would do is pull the mag set cylinder one to top dead center the best way to do it is pull the plug out and look in the hole for the piston coming up to TDC then once you get that set the mag back on the tractor. You should be ready to fire if it backfires reverse the plug wires let us known how you make out.
 

[Greenday]

sounds like a ignition problem
 

[Mike M]

I have had more then one H have intake manifold gasket leakage cause hard starting and poor running and needing to have choke on to run.
 

[Indiana George]

The mag has good spark. When you look at the spark is a blue color so i know it is firing hot and it was rebuilt 2 years ago. yes we have also choked it. The crazy thing is that once it is warmed up it is easier to start as well I could even hand start it when it was warmer. I have read something else about the intake manifold being bad as well? That possibly when the tractor is warmed up the intake manifold expands making it easier to start if there are any cracks in it? any ideas?
 

[Indiana George]

What i meant so say was the intake manifold gasket, not the intake manifold.
 

[buck eye al]

Dad's first tractor was an H and he too had similar chronic starting problems ewven with good spark. My brother and I tinkerd with it when he was away at a seminar and found the plate that covered the LP tank shaped hole in the lower half of the choke plate was broken off. We scrounged up some sheet metal then cut, bent and filed it to make a new plate for it. The spring was still there, just the bottom half of the flapper was gone. That was near 50 years ago & to this day if it doesn't start in just a few turns it's a mag problem or outta gas!

Hope that helps.