john deere h

[70diesel]

working on a h thats is hard to start. just had the carb rebuilt. runs great after a short pull. any ideas in where to start

 

[JDemaris]

Need more info. Magneto impulse not working?

 

[Anonymous-0]

I'm in the same boat 70diesel. In my case I have just taken the generator and starter to our local repair shop. I then want to check the Mag for a good blue spark. I guess if that doesn't do it, I will look at the carb next. 70 diesel, is yours electric start?

 

[George S. in the real NY]

What is the condition of the valves, seats and guides?? I have found that having these items in good like new condition is a big help in getting these old tractors to start quick. 2 Bs, 1H, and a 720 all had bad starting habits done away with by having head work done. The 720 engine was done and I did not touch carb or ignition just to see if they had been ok. Sure enough, starts and runs great. Sooo, you can be looking at a nice project for the winter.

 

[Cockbird_Hunter]

I agree with George...Start with a compression check on each cylinder...Above 80 PSI with less than 10 PSI differential between the two would be good. The valve train especially the valve springs take a beatin' in the H. On the engines I have rebuilt, the valve spring constants were less than 1/4 of original specification. After verifying a good power cylinder & valve train/head, then address carb. & mag. issues

 

[70diesel]

no mine is hand start

 

[Anonymous-0]

Assuming the compression is good and the valves & timing are good, my experiences with the H tell me if they're hard to start either the plugs are bad, the spark is weak or the fuel isn't good or getting there.

I've seen 'em with the "flapper" or relief valve on the choke plate missing, broken or the spring broken. Those will pull start ok but be a brute to hand start. Usually starting best (though still poorly) at no or VERY little throttle. That little LP tank shaped hole in the main choke plate is not supposed to be open. There has to be a spring loaded flapper over it to start well by hand cranking. Dad got his H back in the mid 50's & it too was always a bear to start. When I realized that part was missing & made one for it it's been a peach ever since long as the mag wasn't needing attention.

Ones with weak mags will pull start in seconds and may run like the proverbial top but wear you out hand cranking! Generally true of any tractor mag fired tractor not just the H. Could be dirty points, poor coil ground, bad condenser, bad coil etc. Lot depends on which mag it has too. The WICO C's can suffer from bad bearings too.

As to plugs.... If you're using Champions don't consider anything colder (smaller numbers) than the D21 and even then you better keep it running lean and warm! If you don't ever work the tractor the D23 would be better but the D23 likely won't fit under the plug covers. I've never yet had a D23 foul in any of my tractors.

Hope that helps.

Later.

 

[70diesel]

thanks for all the good info guys. going to get working on it next week just got it in the heated shop today before we get all the snow their talking about.