Farmall bn no spark

[kpoke]

I've got a Farmall bn with no spark . I've not got a lot of experience with these old tractors . I'm not even sure where to find the points in this one. I've inserted a photo . Where are the points here? it's different than the videos I've seen. Thanks

 

[Roadworthy]

My guess would put the points in the distributor. That appears to be the distributor just to the left of the spark plug shown in the picture. The center position of the distributor cap should connect to the ignition coil.

 

[ruffdog]

Here is a video:

 

[DJ54]

Is this a recent purchase, or have you had, and it has ran recently..?? Has it been parked outside, or been in the rain recently..?? Hard to diagnose with what little info is provided.

If it has ran recently, and has sat outside, or got caught in a decent rain, before you tear into it, remove the wire on the side of the magneto, put the screw back in that holds the wire then see if it will start. This IS a magneto, not a distributor. Sometimes when the shut off switch has sat in the rain, even when in the run position it will ground out the magneto, and you'll have no spark.

If it will start, you can shut it off by touching the wire to the head of the screw. If you have some WD-40, spray the switch plunger at the top of the switch, and move from run to stop positions maybe 20-25 times, more WD-40, and that many times again. Doing this multiple times "may" get the switch working again. I've had to do this to a couple of mine, and it did clean up the switch internally.

Hopefully you were careful removing the cap. There is a carbon brush that makes contact with the inside of the distributor cap, that acts like the spring steel contact on a rotor button on a distributor type system.

Here is a link to the Case/IH online parts book for the H-4 magneto you have. CASE IH | Schematic, Manuals, Specifications and Diagrams for electrical system, magneto, international type h-4, special | MyCNHi US Store It shows an exploded view of the magneto. Part #15 is the carbon brush I mentioned.

 

[Mike1955]

Is this a recent purchase, or have you had, and it has ran recently..?? Has it been parked outside, or been in the rain recently..?? Hard to diagnose with what little info is provided.

If it has ran recently, and has sat outside, or got caught in a decent rain, before you tear into it, remove the wire on the side of the magneto, put the screw back in that holds the wire then see if it will start. This IS a magneto, not a distributor. Sometimes when the shut off switch has sat in the rain, even when in the run position it will ground out the magneto, and you'll have no spark.

If it will start, you can shut it off by touching the wire to the head of the screw. If you have some WD-40, spray the switch plunger at the top of the switch, and move from run to stop positions maybe 20-25 times, more WD-40, and that many times again. Doing this multiple times "may" get the switch working again. I've had to do this to a couple of mine, and it did clean up the switch internally.

Hopefully you were careful removing the cap. There is a carbon brush that makes contact with the inside of the distributor cap, that acts like the spring steel contact on a rotor button on a distributor type system.

Here is a link to the Case/IH online parts book for the H-4 magneto you have. CASE IH | Schematic, Manuals, Specifications and Diagrams for electrical system, magneto, international type h-4, special | MyCNHi US Store It shows an exploded view of the magneto. Part #15 is the carbon brush I mentioned.

Very good post. He should have a running machine soon.

 

[jwmorris]

I am not sure why but our ‘48 front mount distributor seems like the tractor that always needs the most attention to the points. Generally just knock the oxidation off and they are good but it’s a PITA to get to them.

Years ago my Father showed me this trick and it’s worth knowing. The incandescent light bulb is for load, the alternating current is the “cleaner”. Even a little inverter will work, just needs to be able to light the bulb. Crank the engine until the light bulb flashes as the points open and close and put it back together.

Keeps the swear jar a little less full.

 

[Williy]

If it has a magneto it could have rust on the mags and need a
cleaning like a lawn mower

willy

 

[Mike1955]

If it has a magneto it could have rust on the mags and need a
cleaning like a lawn mower

willy

Mr Willy could have I guess I have never been any deeper than the points. I have a spark checker. And if you are careful you can do a lot of testing and isolating with it. It is truely an enjoyable experience

 

[Williy]

How far have you gotten for checking for voltage?

willy

 

[Williy]

Mr Willy its just willy I worked for a living

willy