John Deere M timing question

[Steven James]

I have a 1950-51 JD "M". My flywheel has only two timing marks on the flywheel. They read "D-C"(TDC?)and the other reads "PARK", (I think this really should read "SPARK" ). So, when trying to set the point gap, which timing mark do I use???

Thanks for any help!

 

[RLA]

Yes should say spark , set to spark, with #1
plug out rotate dist untill U see / hear or
feel spark.. Install plug, it's ought to run.
Lock down distributor..

 

[RLA]

Yes should say spark , set to spark, with #1
plug out rotate dist untill U see / hear or
feel spark.. Install plug, it's ought to run.
Lock down distributor..

 

[teddy52food]

I would set the stadic timing at TDC.

 

[Hotflashjr]

If you are just gapping the points and have not removed the distributor or turned over the engine since you took the points out you shouldn't need to loosen the distributor if it was in time and ran well before. Install the new points, turn the engine over by hand slowly and watch the points close. Slip a dollar bill between the points while closed and adjsut to the point where the dollar slides between the points with some friction. Not tight, not loose. Tighten the point lock down screw, install rotor, dust shield and cap. If the tractor was not in time beforehand thats when you should try adjusting the distributor.

 

[Anonymous-0]

I would suggest setting it with a timing light. Have followed the book specs and found things not right too many times! Through the years people put the wrong springs in or items just don't work like they used to & these little guys can have an awful lot worng with them & you might not know it from the way they behave.

Deere said to set point gap with a feeler gauge. Then set the flywheel's SPARK mark at the timing mark in the hole. Then rotate the distributor in the running direction so that the points are closed when the rotor is turned by hand to the maximum advance position. Then turn on the ignition with the distributor end of the high voltage wire about 1/8" from grond and rotate the distributor OPPOSITE the running direction until the points just open and it sparks. Tighten the distributor down at this position. Turn off the ignition.

Couple more things.... If the springs are worn, loose, weak or broken, it won't retard properly and may fight the starter or kick you if you hand crank it. You need to assure it retards to 0° for cranking purposes!

I've also seen where original springs were replaced with springs that were too strong or were too loose and it never advanced more than a few degrees after that. With a timing light the spark mark of the running engine should appear in the hole as you near the full speed position of the speed control lever.

Even if you time it like the book says it may not be right and yet they'll not misbehave so badly that you can know something is wrong. They may use more than their normal share of gas and run hotter than normal but even so.... they burn so little how can one know!

Hope that helps.

 

[M-MAN]

Neither one. You set the point gap by turning the engine to where the rubbing block on the points is on the high part of the cam lobe, gap them 19 to 21. There are 2 different style lobes but you set the points the same.

Alway's check the timing afterwards. 1 plug and SPARK centered at full throttle.

 

[leon]

I too have found that it's much better to use a timing light than use the static timing procedure outlined in the manual.

 

[Hotflashjr]

Never checked the timing after on mine because it ran so much better with new points that were opening and closing at the right time. Think I am going to go back and do this!

Can anyone give me a little direction on how to use a timing light on these tractors? Is it just like a car?

 

[M-MAN]

Yep, it's the same. Only difference is whether you have 6 or 12 volts to power the light. You can alway's hook the power leads to the pickemup or lawnmower for 12v.

Basicly what the timing light does is verify your consistency with a feeler guage after the initial run.

 

[bday121058]

First say I'm totally ignorant! Where is this timing hole everyone keeps talking about. I know it's really basic but if you don't know you don't know! Can the #1 piston be in exhaust or in compression and TDC and spark still be visible? My John Deere M won't start and I've been through fuel, electric and cooling. The manual says it's positive ground but the negative post on the battery is going to the body and the positive is going to the starter. (Which will bearly turn over with a new battery.) HELP!

 

[bday121058]

Let me add that I've replaced wire to starter and ground braided wire along with all terminals.

 

[a49deere]

Let me add that I've replaced wire to starter and ground braided wire along with all terminals.

My suggestion would be to get an IT service manual for it. The timing hole, (if the same as a 40) should be on the right-hand side of tractor right behind distributer and looks like a tear drop cover with a single screw holding it on. Open that cover and you will see the side of the flywheel and if you rotate that flywheel, you will see TDC and SPARK on it. That tractor should be positive ground unless someone has modified it with an alternator.

 

[bday121058]

Thanks for the help, I have a manual for it but no where in it does it say where that peep hole is. Now I know exactly! Actually I have three manuals for it and none of them say where they just say look in the hole! The guy I bought it from said it was a positive ground but I know the (-) is going to the tractor body right by the battery box. Crazy!

 

[bday121058]

I have a 1950-51 JD "M". My flywheel has only two timing marks on the flywheel. They read "D-C"(TDC?)and the other reads "PARK", (I think this really should read "SPARK" ). So, when trying to set the point gap, which timing mark do I use???

Thanks for any help!

Okay I'm done. I have worked on VWs all my life, this looked so similar that I thought I could keep it running, but I give up! Dose anyone know someone who works on these old JD's near Anderson or Pelzer SC?

 

[a49deere]

Don't throw in the towel, they are a very simple engine! your original post asked how to set the points. take the distributor cap off and look at distributor cam and look for high spot when cam opens points and set to .20" easy peasy!!

 

[ChrisInPA]

Simple things first: Assuming you have current to the coil and distributor when the ignition switch is on?

 

[bday121058]

Yup, coil has sparkles. Does the flywheel have a "spark" mark for the exhaust and compression stroke or does it only show on number one compression?

 

[bday121058]

Simple things first: Assuming you have current to the coil and distributor when the ignition switch is on?

I have a very strong feeling my 47 JD M had been negative grounded. I now have it positive grounded and it is draining my battery. Didn't I hear on here that their is a way to do something to the cut-out relay to change the polarity back? Does anyone know where I can get a cut-out relay?

 

[ChrisInPA]

With a jumper wire, quickly touch the BAT and ARM terminal on the generator. There should be a spark when you touch the ARM terminal. Then it’s polarized.