M100 Run Motor Works, but Still has Issues

[Sweet Pete]

10 milliliters isn't a whole lot. Fill each funnel quickly up to the brim, then wait for the oil to drain away. Repeat 4-5 times per funnel.

Again....
Try shorting out the start motor resistor,alligator clip across the leads.
It's under the metal cover on the left end of the genny as seen from the back.
They gain resistance as they age.....
Sometimes it's just that 50-100 RPM that holds you back from a 'run'!One hand of course...that's AC on those terminals!
Done this more than once on an M3/M100.
It takes a minute to try.

[jacobchapman]

Long-time bump, but I've had some more time on my hands lately to revisit this.

Again....
Try shorting out the start motor resistor,alligator clip across the leads.
It's under the metal cover on the left end of the genny as seen from the back.

I've tested this multiple times to no avail. The resistor meters out to 250ohms on the dot.

With flywheel disconnected, the TWG spins up to speed and takes about 15 seconds to come to a halt. With the flywheel springs connected, it struggles to get to to speed (it eventually gets there) but then comes to a halt after only 4-5 seconds.

The vibrato scanner is removed.

Is it time to look at replacing the run motor? I'm feeling at the end of my wits here.

[muckelroy]

Ok, wit's end advice will require you remove the run motor and scanner in one assembly, and set them on a surface outside the organ.

1. Remove scanner.

2. If you grasp the flywheel, can you move it left to right (laterally)? If so, how much? There should be about 3 to 5 mm of movement free there. Previously, you re-tied an oiling thread. Do both sides of the run motor have an oiling thread?

3. It is most common for the flywheel side bearing to be stuck. If stuck, spinning flywheel will spin bearing along with it. Is this happening? If so, your previously tied thread won't last very long and is probably broken off by now.. You will need to re-tie the thread, soak that thread in oil and naphtha. You could also try tapping the shaft gently with a small rubber mallet on both sides to get it moving freely inside its bearing but be very cautious when doing this.

4. Are you sure the run motor wires are soldered to the correct terminals on the line panel?

If the run motor turns freely when power is turned off, and you are sure of the wiring, you could try wrapping a shoelace around the flywheel, pull it to give it a "running pull start" this way, then hit the run switch and see if it runs on its own. I know that sounds crazy but it's really not. I've never done it but I know people who have, when their start motor is acting up and they're desperate.

[jacobchapman]

Ok, wit's end advice will require you remove the run motor and scanner in one assembly, and set them on a surface outside the organ.

1. Remove scanner.

Done. I removed the vibrato scanner a while back, and have just now removed the run motor-flywheel assembly.

2. If you grasp the flywheel, can you move it left to right (laterally)? If so, how much? There should be about 3 to 5 mm of movement free there. Previously, you re-tied an oiling thread. Do both sides of the run motor have an oiling thread?

Hmm, I can pull the flywheel along it's axel just barely. Is this the lateral movement you're referring to? If I were looking at the face of the flywheel, from the TWG, I can move it in/out but not left/right. The flywheel doesn't spin freely, but I can turn it by hand. It makes a slight clicking sound like winding a clock. If I try and give it a good spin it stops as soon as I let go.

3. It is most common for the flywheel side bearing to be stuck. If stuck, spinning flywheel will spin bearing along with it. Is this happening? If so, your previously tied thread won't last very long and is probably broken off by now.. You will need to re-tie the thread, soak that thread in oil and naphtha. You could also try tapping the shaft gently with a small rubber mallet on both sides to get it moving freely inside its bearing but be very cautious when doing this.

The bearing on the flywheel side does not seem to be spinning. And I have not yet attempted to retie the strings, just been dropping little amounts of oil directly on to the bearing.

4. Are you sure the run motor wires are soldered to the correct terminals on the line panel?

Yes. Terminals 4 and 7 if counting from the left.

If the run motor turns freely when power is turned off, and you are sure of the wiring, you could try wrapping a shoelace around the flywheel, pull it to give it a "running pull start" this way, then hit the run switch and see if it runs on its own. I know that sounds crazy but it's really not. I've never done it but I know people who have, when their start motor is acting up and they're desperate.

This is so crazy I love it. However the flywheel doesn't have any momentum at all without being manually turned. See above.

Thanks for the reply!.

[muckelroy]

Hmm, I can pull the flywheel along it's axel just barely. Is this the lateral movement you're referring to?

Yes that is what I mean. You should have some movement in this direction.

The flywheel doesn't spin freely, but I can turn it by hand. It makes a slight clicking sound like winding a clock.

There should be no sound. Maybe your bearings are just dirty. It seems to me your flywheel-side bearing is stuck and the axle and flywheel-side bearing are spinning as one, but you insist that this bearing is not spinning, so I am not sure what is going on.

Given how much time and effort you've put into this, you should probably buy a replacement run motor.

Maybe these bearings need days or weeks of more oil soaked into them. Maybe a gentle mallet tap like I said before, to free the axle some more. (Key word, GENTLE). It is also possible that these bearings are damaged beyond repair and need replacement, but that's a big job requiring tools of a machinist or someone who knows how to fit and press replacement bearings.

[jacobchapman]

You guys!! I ordered a replacement run motor off eBay and hooked it in and the organ spins! It's making beautiful noise for the first time since I bought it!

I tied some new cotton string on where it had previously broken, and I've connected the vibrato scanner back up to all it's points. Thanks for all the help everyone. It's time to celebrate. :D

[Sweet Pete]

That is great news! Enjoy that M100,a classic instrument everyone agrees.