John Deere M won't start - Update

Hotflashjr · Nov 29, 2016

Went back to help my friend get his M moving. Double checked spark and fuel and no airflow issues. Put on a new gasket between carb and manifold and manifold and block. Boy they needed it anyways. No go after a spin or two on the starter. Decided it was time to take off the valve cover. When we did we realized cylinder 1 had a keeper off the intake valve and a slightly bent push rod. So cylinder 2 was making all pressure we were seeing but cylinder 1 was not taking in enough fuel on the intake stroke.

This M has a plow on it so we got that off the tractor and now just need to go back and winch it on the trailer and get it to somewhere the engine can be torn down.

Anyone know of a supplier of a rebuilt head? I don't think the head itself is damaged as the bend in the pushrod is up high but I have limited knowledge on successfully rebuilding a head on one of these. If we can find one that has been totally redone that is the route he plans to take.

Thanks for all the help!

Russ from MN · Nov 29, 2016

Before I would tear it apart I would loosen up the valves with some penetrating oil, straighten the push rod and start it up. You might not have to tear it apart. Has it been sitting for awhile? Sounds like the valve just stuck, pretty common on old JD's. Penetrating oil and a soft hammer will usually loosen a valve.

M-MAN · Nov 29, 2016

Alway's remember KISS. You are planning on spending pert near half a grand total on a guess. Eliminate the guess first.

Your local automotive machine shop can rebuild that head easily much cheaper than you can purchase another one that may or may not be in as good a shape. My question is why not replace the keeper, straighten the push rod, add oil/penetrant on the valve top and through the intake port(all), hit valve with a brass hammer a few times to make sure it's free, set the lash and fire it up. Once she's ran enough to beat the rust off the valve faces you can check the compression and you will know if you need to pull the head. My guess is you won't need to.

Hotflashjr · Nov 29, 2016

It is not my tractor or money and my buddy thinks this is the best/easiest answer. I will try and talk him out of it a bit more but you can only lead a horse to water.

M-MAN · Nov 30, 2016

That is true. In the end it's alway's the owners call.

donjr · Dec 11, 2016

Try Wengers in Pa. 800-451-5240. They have a lot of JD parts and can ship them the same day in many cases.....

John Deere M won't start - Update

Hotflashjr

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Russ from MN

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M-MAN

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Hotflashjr

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M-MAN

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donjr

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