1948 John Deere magneto timing

[trocken10]

(quoted from post at 13:22:45 11/24/23) Let's recap.

You have compression on each side.
You have impulse tripping at TDC on the left hand (flywheel) side.

Ok, have you visibly observed the spark plug firing when the impulse trips? If so, what color is the spark? It should be blue. Sometimes it is hard to see in the daylight, so try to find a way to shade the plug so you can observe it. If isn't a good blue spark, you have a weak spark, possibly due to many things, among them failing condenser, corroded points, corroded contacts on the cap, weak impulse spring and so on. You are using a solid metal core plug wire, right? Mags require solid metal core wires.

If all that checks out, access the inlet side of the carb and shoot in a little starting fluid while moving the left hand cylinder through the intake stroke and then run it through compression and see if it fires. We are just trying to see if it will fire, not start the engine, and it should if you have compression and spark at TDC on the compression stroke. You may need to do it a couple times. If it still doesn't fire. then obviously something is still wrong with either spark or compression. Possibly the spark plug as some have been known to spark outside of the engine but not when under compression.

I am showing 55 or so psi on each cylinder. New pistons and rings, and had the head machined. New valve springs, magneto has been recently rebuilt. Had bought new wires, just tried it with the factory wires, that were on there when it last ran. Spark is a nice blue on both sides.

Tried the ether, as I cranked, there were a couple of times when it cranked quickly, like it was going to fire, but nothing.

 

[rustred]

If youre sure its timed correctly with the spark
happening at tdc on compression. Verify with a wire to
feel the piston position when the spark happens. If
correct give it an ounce of gas into each cylinder and try
it. U have not said if the plugs are dry or wet. Plus
starting fluid dont do anything with out fuel. U keep
saying its a blue spark , ya ok but verify its happening as
I asked. Have the plugs out with the wire hooked to the
one youre watching. Have someone turn the flywheel
very slowly while u have a wire in the hole to feel the
piston coming ahead on compression. The spark should
happen exactly at the same time the piston reaches tdc.
Have u done this ???

 

[trocken10]

(quoted from post at 21:34:49 11/24/23) If youre sure its timed correctly with the spark
happening at tdc on compression. Verify with a wire to
feel the piston position when the spark happens. If
correct give it an ounce of gas into each cylinder and try
it. U have not said if the plugs are dry or wet. Plus
starting fluid dont do anything with out fuel. U keep
saying its a blue spark , ya ok but verify its happening as
I asked. Have the plugs out with the wire hooked to the
one youre watching. Have someone turn the flywheel
very slowly while u have a wire in the hole to feel the
piston coming ahead on compression. The spark should
happen exactly at the same time the piston reaches tdc.
Have u done this ???

I have had the plug out, and saw that the spark is happening, when piston is at TDC. The plugs are dry after cranking it.

Are you saying to put an oz of gas in cylinder, with a wire lead off the spark wire, inserted into the block?

 

[Rich'sToys]

He's saying to put a piece of stiff wire into the cylinder against the piston, and turn the engine over. By watching the wire move, you'll be able to tell exactly when the piston is at TDC. Then take that wire out. If the plug is firing at the right time, put the gas in the cylinder, then put the plug in, hook the plug wire up, and try to start it.

 

[rustred]

Wow,! now I understand why it wont start. Get a manual
or a mechanic helping you. I Tryed to explain everything
as simple as I could. Now I will ask how u set the valves. ?
1 can see u have no experience understanding how to
time an engine nor follow what I am explaining.

 

[Gomer]

This is one of the few times anyone has mentioned that it fires on the compression stroke and the exhaust stroke. When someone says to be sure to get #1 cylinder at TDC on the compression stroke, I always wonder why they harp on this, It does not matter on most of the older tractors.

 

[FarrviewSouth]

Given the frustration evident, I almost hate to respond :. But when I put my new to me A back together two years ago, it drove me crazy. It would not
fire up, I checked everything mentioned above triple times and I am not new to old equipment. Had good blue spark when testing the spark against
the block on both cylinders, had fuel, had compression. I was beyond frustrated. As a last resort, I put on two new plugs..ran like a top just plain
purred.damn old equipment:>

 

[Kansas rhody]

So are the plugs wet after trying to start? I was pulling my hair out on my 49A , put in a set of new plugs and nothing. Went back to the old plugs, different brand, and it fired right up, what plugs are you using?

 

[trocken10]

New set of plugs are dry when trying to start.

 

[trocken10]

I can see piston at TDC with spark plug removed, and magneto impulsing, and spark plug sparking.

I have attempted a little gas in the cylinder, and put the plug back in to try and start, with no luck.

 

[trocken10]

(quoted from post at 23:31:57 11/24/23) Wow,! now I understand why it wont start. Get a manual
or a mechanic helping you. I Tryed to explain everything
as simple as I could. Now I will ask how u set the valves. ?
1 can see u have no experience understanding how to
time an engine nor follow what I am explaining.

Rustred, frustrations noted.

 

[rustred]

Yes frustrating , as youre not following instructions. U
can see all that ya ok is it happening when it should ?
Tell me that. Not going to run till its timed. U still did not
verify the correct timing.

 

[trocken10]

Yes, I turned the flywheel, heard the magneto impulse, saw that it sparked, and then looked and saw the piston was at TDC.

 

[rustred]

if your so sure its all corrct/ ,give it a pull with another tractor. it will start or keep backfiring due to timing. not really sure how u
can see the piston. i also asked how u set the valves. u are replying with no spec's of your work.

 

[Rich'sToys]

(quoted from post at 19:48:08 11/25/23) Yes frustrating , as youre not following instructions. U
can see all that ya ok is it happening when it should ?
Tell me that. Not going to run till its timed. U still did not
verify the correct timing.

Okay. let's back off a bit here. No need to lecture him like a third grader. He may not have the experience as some others on here, but our job is to help him figure it out, not preach to him.

 

[rustred]

ya well i am all for helping a person but they must work with me. appears i am the one that wants to help him. cant help when a person dont
follow directions, then i cant proceed. and again yes that is frustrating, and not lecturing. lots have opinions here but never follow the
problem through. ooh well.