John Deere 70 d pony motor

Brian604

New User
I have a 1955 John Deere 70d with pony motor I have two
problems with it the first is the only way it will run is with the
choke on and the rpms are not that high when does run. The
2nd thing is the gear won"t go all the way out to turn the
flywheel. It only comes out a Lil bit where coners touch can
anyone help me
 
Carb needs to be rebuilt and/or points and plugs need to be replaced. Are both coils hot? if not, replace thoise also. Does it have good compression?
If recall correctly, the 70 D had the single lever which is hard to get adjusted but works when it is. There are adjustments for the pony in the JD service manual. Unless something is worn bad or broken, sounds like adjustments would put it back working.
 
I tuned it up new every thing plugs wires points coils the works. Were is the adjustments on the transmission so it don't grind the flywheel and gear down
 
adjust the turnbuckle right where the the gear comes out to the flywheel, and/or the one attached to the engage lever
 

I know my 720 has 2 levers and yours has one..but I have the absolute Least chance of grinding gears, if I engage the Pony at just above Idle (after it has warmed-up some)..

Ron.
 
if it will only run with choke it is not getting enough fuel.. either the load and or idle screws need adjusted or the carb needs cleaned .the adjustments for the flwheel are complicated with the one lever starting. the bolt to the starting lever is part of it. Part of it is in behind flywheel cover near the pinion is kind of a turnbuckle .it took a lot of fiddling to get mine right.luck Paul
 
About 20 pages into the service manual is a nice explanation and photos of how to go about adjusting the pinion linkage. You may have a pony clutch adjustment issue as well.

On the carb, the load jet is in the very bottom of the bowl, and tends to get debris filled/clogged. Even the best ponies I have seen tend to be cold-blooded, liking choke until warmed up. If I keep mine tuned to start and run well when the tractor is warmed up, it likes its choke when it starts cold.
 
I hope FIT doesn't mind but I second all he says here and would like to add, it's been my experience that they are VERY sensitive to float level adjustments!

If the fuel level is low in the bowl (float not properly adjusted) you'll have to choke the livin daylights out of 'em! The basic load needle adjustment is 5/8 of a turn open. I've seen 'em open 4 turns and clean as a dinner plate inside but still need lots of choke because of wrong float adjustments!

Of all the things I've tried, I have had the best luck setting fuel levels on these little guys by using clear vinyl tubing inserted through the top of the assembled carb through the hole left by complete removal of the load needle. Start a siphon then "up end" the tube's outlet & view the fuel level like reading a U tube manometer. Make sure there are no bubbles of course.

Hope that helps.
 

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