1650 PTO clutch
 

I just bought a 1650 that's in very usable condition. I noticed that while mowing the battery was discharging. The electric clutch needs some power, but I was surprised that the generator wasn't keeping up. With the PTO off, the ammeter showed a charge. By the time I finished mowing (about 1 hour) the battery, which was new, could barely strat the tractor. Any comments or suggestions?

Sounds like there is a short with the PTO clutch somewhere.

Good luck,
Keith

The Elec PTO under normal conditions would NOT impact the charging system that severe. The approximate current draw is ~3-4 Amps.

To test the PTO, simply unplug the connector. If you electrical system still discharges, then you have a Charging Issue as opposed to an Elec PTO problem.

Try that and let us know.

With the 1650 running, and the PTO switch off, the meter shows a charge. Charge rate is dependant on engine speed as expected, so the generator looks OK. When the PTO switch is moved to "on", the gauge shows an immediate and substantial discharge. I'll pull the clutch wire off and repeat this to see if I can find the source of the short.

MFP8055:

You have one of two situations.

(A) You have a short in the circuit leading up to the Elec PTO
or
(B) The Elec PTO is shorted itself.

See this link for Elec PTO Information.... PTO

Yup, that's how I see it too. I'll pull the connector and see what that shows. Thanks for the link to the PTO diagram. That will be very helpful.

I tried a few things with the electric PTO: With the connector unplugged, the ammeter does not show a discharge condition when the PTO switch is on. My conclusion is that the short (or high current drain) is in the electric clutch itself. Any thoughts on where I should go from here?

The electric clutch is pretty much a replacement item. you can't really work on the electromagnet. The only thing I would check is where the wire comes out of the electromagnet,to the connector, it may have been pinched between the block and the mounting bracket.

Good luck

If you have a fairly accurate VOM or DVM, you can check the resistance of the Elec PTO per the reference link above.

You can actually re-wind the coil. I haven't done it, but if you get the same diameter of wire and get approximately the same number of turns, you can fix that.

I've got a good digital multimeter, so I'll start by checking the resistance. After that, It's probably a search for a good used part.

I removed the electromagnetic clutch and measure the resistance of the field coil as per the CC instructions. I found 0.9 Ohms resistance vs. a factory spec of around 3-4 Ohms. The lower resistance indicates greater current flow and thus, higher drain on the battery. The plastic potting material on the field coil was cracked in a few places also. Does this sound typical? Is the resistance I measured that out-of-whack?

IF your VOM or DVM is accurate, then anything less than 3 Ohms indicates a short.

If you want to spend some extra time on this, you could remove the field coil assembly from the Tractor. Wash and clean it up real good. Let the Field Coil dry (or blow dry). Then retake your ohmerage readings again. If still less than 3 Ohms, then the Field Coil is toast.

IF you readings are in the Factory range (3 to 4 Ohms), then you can seal the cracks in the potting material with something like JB Weld.

I have the coil off the tractor already, so I'll give the clean-up route a shot. There are only a few cracks where the windings are visible, so I should know if it will work or not fairly soon. Another question I have regards the brake plate. My clutch dragged on the plate when not energized. I assume the plate needs to stop the clutch when the PTO power is off, and have no contact when engaged. Any tips on adjustment?

Your analogy is correct on the Braking Design.

Refer to the Link above for adjusting the Brake Plate Clearances...

:ThumbsUp:

Sorry to have taken this thread in a new direction. Did I miss the link you supplied?

In post #5, Rolland hyperlinked the word PTO in the last sentence of his post.

I use an extra long feeler guage, long enough that it passes thru 2 of the 4 slots on the brake plate at the same time.

I just picked up a used clutch on ebay. It looks like heck, but the internal resistance is right on the mark (3.2 ohms). Need to patch the potting on the coil in a few places, and the power wire is badly frayed. Some surgery required to get it in shape, and not much wire to work with. Still, it looks like I've got a solution to the problem.

Weve used epoxy in the past with good results. Ive also used glyptal on windings before. I coated the coil in this and baked it in the oven for an hour on 200 then let it dry. The oven allowed the glyptal to flow around the wires to help with insulation.

I suppose any non-conductive potting material that will hold up under the heat and oil exposure would work. I'm not familiar with glyptol. What is it?

This should help


http://www.caswellplating.com/aids/glyptal.html

Last time I used it was on a submerged oil bathed yamaha stator winding and that was 8 years ago. Saved the stator and saved me 350.00. Bike still works and charges great. I know its expensive, but for my applications and a 250.00 pto its worth it.

I can see the wisdom in using the Glyptal, but I took the cheap route and potted the coil in JB weld. It went on well and cured hard as a rock. The resistance is still at 3.9 Ohms, so I didn't screw up the clutch during the repair. It will be awhile before I test it since the 1650 is disassembled and getting some much needed TLC. Steering box rebuild and an engine inspection are next. Good machine and a lot of fun to work on.