Today I played with the tractor a little more. I first tried engaging the clutch, but I did not see any movement from the snow thrower belt. I removed the belt from the snow thrower and watched the clutch drive action when I engaged the clutch. Without the snow thrower belt attached, the clutch engaged and moved every time I pulled the switch.

I then inspected the snow thrower drive system. I moved the 2nd stage (blower section) by hand, and it seamed to move pretty smooth.

I then attached the snow thrower belt to try again. The clutch did not engage. Then, with the engine off, I pulled the snow thrower belt to move all of the pulleys. Then I tried pulling the clutch switch, and all the belts moved. I did it repeatedly, and it seamed to work every time.

I then went out a couple hours later to try again, and it did not work. The snow thrower belt did not move once the clutch was engaged. At this point, I did not try to manually move the snow thrower belt, because I know that if I do, it would work, as I mentioned above.

A couple other points that I'll mention are, that during the storm, this problem was first noticed after I broke a shear bolt. After the shear bolt repair, the snow thrower belt would not move, just as I explained in the above symptoms. My other point is that I originally thought that the problem my have been the belt that is directly above the snow thrower belt. I thought this because, when I looked down there, that belt was loose, and I also noticed some greenish string on some of the bolts in that pulley interface network that then drives the snow thrower belt. The belt in question actually looks pretty strong, and I learned later that the belt is loose until the clutch engages. But, that string, I'm still pretty sure came from that belt.

My experience with that clutch is only on my mower, but I suspect that the basic mechanism is the same.

Recently I had to remove the clutch to do some other repairs. I found that the power wire to the clutch was cut almost totally through about 2 inches from the clutch. The insulation had been 'stripped' from the wires. Since the wire was securely tie-wraped away from the pulleys I have concluded that the damage must have occured sometime in the past when the ground drive belt broke or mowing debris got into that area.

So, how might that apply to you? I 'sounds' like you might not have enough current to always engage the clutch fully. That just might be caused by a partially severed cable to the electric clutch. If your 'greenish string ' is from a damaged belt that could also be a clue....

Or...your clutch may not be engaging because your battery/charging system is not 'always' strong enough to engage the clutch. These clutches take A LOT of current.

Hope this helps....

Galaxieman

Sounds to me like a wire problem - check the connections at the clutch, as well as the other ends of those wires. Pay particular attention to the ground wire. If you have a meter, be sure you're getting twelve volts at the clutch.

The part about "The clutch always makes some sort of noise when you pull it out." almost implies that the clutch is failing (or has failed)mechanically.
Especially considering that during one of your "checks" the clutch actually engaged when tried without the belt in place.
Do the voltage checks to make sure you are getting battery voltage at the clutch. If your voltage check shows you are getting battery voltage on the clutch "hot wire", check the ground wire side of the chassis harness to be certain that the place where the ground wire connects to frame has not gotten loose (assuming this connection is done when snow thrower kit is installed).
If all that tests OK, check the two wires that disappear into the clutch with an Ohmmeter to be certain the windings are not open or shorted. A reading of zero resistance indicates a short. A reading of "nothing" or infinity indicates the windings are open.
It's also possible that the friction material of the clutch is worn out, burned/glazed, or has shredded.

Just to expand a little on mownie's post....When I recently repaired the broken wires on my clutch, I measured the resistance of the coil. It measured just about 3 ohms. If your clutch is OK you should get a similar reading. On my mower the clutch 'plugs in' at a connector just below the battery. That is the place to measure because it will check both the clutch and the wires too the clutch.

Today I did the following measurements.

Followed the cable from the electric clutch to a molex type connector which would then connect to the switch (PTO I believe it's called). I did not remove the clutch, but did inspect the cable with my hand, all the way to the clutch. I could also see (visually), a good portion of the cable, all the way to the clutch, minus about a 1/2 inch which is connected to the clutch.

I also measured the resistance of the clutch at the molex connector, and got a solid 3 ohms. I also jiggled the wires at the clutch to check for intermittence, continued to get a solid 3 ohms. I also moved the belt while monitoring the resistance. I did see it change, but figured this would be due to properties of the inductor while becoming energized from my mechanical influence.

Then, I plugged the clutch back in, and hooked my meter up to the molex connector (a parallel voltage measurement). When I pulled the switch, I would see 13.6Vdc. I would see this same voltage whether the belt would move or not.

When the belt would not move, I also shut down the tractor and unplugged the clutch at the molex connector, and measured the resistance. I got a solid 3 ohms.

Also, when I pull the switch, as I mentioned before, the belt would always tighten. Today, I noticed that those times when the belt does not move when I pull the switch, sometimes it will begin to move after a couple seconds. Slowly at first (short time), then normal speed.

There are also times when I pull the switch, my tractor's engine will rev a little louder to compensate. These times, the belt always moves. The times when the belt does not move, there is no extra rev. This "rev" is just a quick blast of extra power from the engine. It spikes, then goes back to normal volume or power.

Today, I did want to verify the connection and operation of the clutch by monitoring the current draw when the switch is pulled. When I set up the measurement, I noticed that my meter only went to 200mA dc, I did not follow through with the measurement. If you guys think this would be a necessary measurement, I could borrow a meter to get the data. How much current should I expect during that measurement?

E-mail me for a PDF guide to testing and "possible adjustment" of these clutches.
Keep in mind that this manual is for Warner brand clutches. I don't know if the clutch you have is a Warner (or not), but it may help you in a generic sort of way.

First of all...3 ohms is good. That is what my good clutch reads.

"Today, I did want to verify the connection and operation of the clutch by monitoring the current draw when the switch is pulled. When I set up the measurement, I noticed that my meter only went to 200mA dc, I did not follow through with the measurement. "

Simple Ohm's Law says that you should always show a current draw of about 4 amps when the clutch is engaged.

I am sure you know that there are other 'factors' that could affect the operation of the clutch. Some of them are....seat switch, the pto switch itself, the 'brake pedal depressed' switch, etc. If it were me, I would eliminate all of them by connecting power directly from the battery to the molex connector when the motor is running. This will eliminate all of the 'safety' lockouts as being the problem or indicate that they are the 'culprit'.

Yesterday I did the following measurements.

I measured the current draw of the electric clutch. When I first pulled the switch, the belt did not move, but the clutch did make its typical noise and did draw 4.2A.

I tried a few more times and the belt did not move. I then manually moved the snow blower belt as I described in my earlier posts. I tried to pull the switch again and still no movement of the belt. After a couple more times the belt finally started to move, also slowly for a brief moment, then reaching normal speed slightly after (as I described in an earlier post). During the moving belt condition, the current draw was the same, 4.2A.

It seamed that if I disengaged the switch after the belt has been moving and then pulled the switch shortly after, the belt would move almost every time. But if I waited a bit longer, the belt didn't move.

I also removed the snow blower belt and when I pulled the switch, the belt would move every time. Also, with the snow blower belt removed, I measured a current draw of 4.2A every time I pulled the switch.

I also did as BriggsGalaxieman suggested and bypassed the PTO switch by hooking the electric clutch directly to the battery when I wanted to engage the clutch. By doing this, the performance did not change. I tried a few times. The belt never moved, but the clutch made the same sound as if I pulled the switch. I did not bother trying to produce a moving belt measurement because I'm confident that it's the same.

I also did a measurement of the current draw over a time of about 20 minutes. The current draw slowly drifted from 4.2A down to 3.7A, where it seamed to stabilize. During this measurement, I did disengage and engage the clutch a few times, just to see if there were any other levels to be aware of.
I would also like to mention that the performance of the electric clutch was the same from the time the tractor first starts up, to being fully warmed up.

I also removed the snow blower attachment and belt to have another look. I manually moved the second stage blower section and observed the augers moving. I could not see anything that would cause a lockup of the belt.

I also checked out that adapter section that interfaces the electric clutch with the snow blower belt. Everything moves pretty smooth there too. My previous measurement with the snow blower belt removed also proves this section is working perfectly.

My next move is to remove the clutch and use the manual that mownie sent me, to see if I can make any improvements.

Sounds like you are getting there....4.2 Amps is just about what you should see whenever the clutch is engaged, even if the snow blower is not moving. The current draw of the clutch coil would normally be independant of how successful the PTO/clutch is in moving it's 'load'.

You wrote:

"I also removed the snow blower belt and when I pulled the switch, the belt would move every time. "

This sure seems to indicate that the problem is with whatever mechanism(s) the snow blower belt is trying to move....

Galaxieman

Yesterday, I did the following.

I removed the electric clutch and brought it inside to inspect it with the feeler gages. I noticed that the 0.023" feeler gage went in pretty easy. My feeler gage did not allow me to increment very easily, so I just assumed that the gap could have actually been a little bigger at times.

Next I followed the procedure for tuning the air gap and set them for 0.012". I then inspected the results of the tuning, and verified that I was between 0.005" and 0.023" at all 3 windows.

Today, I did the following.

I installed the electric clutch and re-installed the snow blower attachment.
Note: I did not remove the electric clutch to snow blower interface. I only pulled the belt off the electric clutch.

After the installation was complete, I verified everything was correct before testing operation.

During the functional check, the belt moved every time. I even tried letting the tractor run for a few minutes without the electric clutch engaged and tried again. The belt moved. There were a few times when it looked like the belt did not move right away. This may be because I was watching extremely close and anticipating failure. The important thing is that it moved the very first time, and every time.

I feel pretty confident that this problem is fixed and that the culprit was the out of tolerance air gap of the electric clutch.

Thank you Galaxieman, mownie, and twelvegauge for your help. I really appreciate you all taking the time to advise me.

Thank you,
Dave

See there Leon.....you ain't so thick after all! :^)
Thanks for the update.

This seems to be the most current (2011) posting on this topic (according to Google 2015) so I'll post my remark here....

Don't buy a new clutch before trying this... if your symptom is an intermittent clutch, give the 3 gap adjusting nuts a half turn clockwise (lifting upward) and see if it's just out of tolerance. After a season of intermittent clutch engagement and after ruling out electrical problems that's all it took to get my Craftsman GT-3000 cutting again. [a clue might be that the Ammeter indicates 4-8 amps draw with a good battery, the engine off and a weight on the seat but you don't hear the clutch click].