Grasshopper zero turn clutch question - clutch or solenoid/electrical?

Buxus · Oct 30, 2022

I have a 2008 928D. Love the mower, hate the clutch.

I purchased it used with 200 hours on it in 2016, and had to have the clutch replaced 100 hours later in 2017.

Now it's five years and 600 hours later, and today the blades would be spinning, and then just cut off, even when over already cut grass. Sometimes if I turn off the PTO switch and then turn it back on, the PTO engages and blades will work for a minute or so. Sometimes turning the PTO off and on does nothing. After a few times the PTO usually comes on but soon the blades stop spinning.

I assume it's either the clutch or something electrical with the clutch. Does this sound correct?

I always engage and disengage the clutch at idle speed.

I don't have the time nor know-how to investigate or change the clutch myself. Hopefully I'll be able to have it fixed soon.

Is there any way based on the description above to know if it's electrical or the actual clutch?

Eagle1 · Oct 30, 2022

Since you said "I don't have the time nor know-how to investigate" I say no way to know with out some testing and looking at the blade drive system. Heck it could even be a belt and/or idler in the drive system.

Will S · Oct 30, 2022

Buxus said:
I have a 2008 928D. Love the mower, hate the clutch.

I purchased it used with 200 hours on it in 2016, and had to have the clutch replaced 100 hours later in 2017.

Now it's five years and 600 hours later, and today the blades would be spinning, and then just cut off, even when over already cut grass. Sometimes if I turn off the PTO switch and then turn it back on, the PTO engages and blades will work for a minute or so. Sometimes turning the PTO off and on does nothing. After a few times the PTO usually comes on but soon the blades stop spinning.

I assume it's either the clutch or something electrical with the clutch. Does this sound correct?

I always engage and disengage the clutch at idle speed.

I don't have the time nor know-how to investigate or change the clutch myself. Hopefully I'll be able to have it fixed soon.

Is there any way based on the description above to know if it's electrical or the actual clutch?

May not have anything to do with the problem, but I've got a Woods Mow'n Machine (diesel) that I bought new in 1997/98. It has about 1000 hours and is still running the original PTO electric clutch. My owner's manual states to engage the PYO at full power, which sounds counter-intuitive for long service life, but that's what I have always done. Supposed to "burnishes" the surface of the clutch.

If you have average mechanical skills, seems you could replace the clutch yourself and save a bunch of money.
But you would need to do a little diagnostics first. When the blades stop spinning, you (or someone else) needs to look at, (not touch) the PTO, to see if it is still engaged. If it is, I'd say it's worn out. If it is not engaged, there is an electrical problem causing it to lose 12volts, and disengage.

But if you sre not confident in doing any of this, it's best to find someone who can diagnose and repair, for you. An auto mechanic would have no trouble doing this, if yo know one.

mini14 · Oct 30, 2022

I have a scag tiger cat with original clutch and prob ar o under 5000hrs. I have adjusted the air gap once. Sometimes the pto switch goes bad. Look to see if yours is an adjustable clutch but it shouldn't need adjustment with such low hours.

CobyRupert · Oct 30, 2022

Pull the plug off the pto and see if 12volts is there when you flip the switch. If it’s not there, it’s an electrical problem. If it is there when it’s suppose to be, it’s probably a mechanical problem.

Buxus · Oct 31, 2022

Thanks, guys. I'll report back, hopefully soon.

Buxus · Dec 17, 2022

And so the saga continues. The dealer looked it over, and said it was an electrical problem. He said he changed the seat switch and PTO switch and that it was fixed. He returned it to me after a few weeks and it was exactly the same. I'd mow for about 10 minutes and the blades would stop turning. I would then stop, power down, and sometimes they would restart after I turned the PTO switch off and on. Sometimes not. It never ran for more than 15 minutes without the blades cutting out.

The dealer said fixing it was trial and error, and he said he'd try to get a multimeter on it. After a week or so he called me and said it was an electric problem within the clutch. He replaced the clutch at cost of material and charged me no labor and no second pick up drop off fee.

Today I tried if for the first time, and it ran beautifully for about 45 minutes, then did exactly the same thing. The first time today the blades cut out I was able to get them re-spinning again by turning off the power. After that they cut out after 5 minutes, and I haven't been able to get them to go again.

I am hoping that if it stays "broken" they will be able to find the problem. It seems like the dealer is trying to do right by me. Is it usually this hard (and expensive) to solve a problem like this? Any suggestions?

Richard001 · Dec 18, 2022

Those clutches draw a lot of current. Next time you go out to cut, take a voltmeter along with you. When the clutch drops out, shut off the engine and then measure the battery voltage. Here info on lead-acid batteries:

A battery’s condition can be monitored by checking the electrolyte’s specific gravity with an inexpensive D-I-Y battery hydrometer to determine the percentage of sulphuric acid it contains.

A fully charged cell at 80 degrees F would show a specific gravity of 1.265. If all six cells are fully charged, an accurate digital voltmeter reading of battery voltage would show 12.68 volts.

Specific gravity for a 50 percent discharged cell would drop to 1.19 and battery voltage would fall to 12.24.

When specific gravity reaches 1.12, the cell is fully discharged and battery voltage falls to 11.89 volts, assuming the specific gravity is the same in all six cells.

Because specific gravity is affected by temperature, subtract .004 per 10 degree drop below 80 degrees F.

If your battery is not showing a full charge at about 12.4 to 12. 6 volts, then I would suspect the alternator or the regulator is not working properly.

Richard