Chipper/Shredder Centrifugal Clutch

[Stevedore]

I have a MacKissic Mighty-Mac chipper/shredder that I bought new last year, used it about 3-4 hours so far.

It has a centrifugal clutch on the engine shaft to allow for easier no-load starting.

The last couple of times I used it, I noticed that as it slows down after I shut it off, there's a bit of noise coming from the engine area. Hard to describe, but sort of a rattling/groaning noise like you might get if you spun a mower wheel on a dry axle, if that makes any sense.

I took off the belt guard, & could see that there was dry black crud coming out around the shaft bushing area of the clutch. I took the clutch apart, & the inside was covered in the same stuff, sort of like dried out dirty grease. The clutch shoes were covered with it as well. It was clearly coming from the clutch shaft/bushing, as I could see tracks radiating from the center.

I cleaned it all up, and I'm not sure what to do about lubrication when I reassemble it. The clutch bushing appears to be an "Oilite" type bronze, which I'm used to putting a bit of oil on. Can someone correct me if I'm wrong?

And I'd doubt that the clutch shoes or outer housing should have any kind of grease or oil on them. Again, someone please correct me if I'm wrong.

This situation seems odd for something with so little use; I'm assuming that the clutch assembly was possibly over-lubed at the factory, but who knows.

I attached a couple of pics of the cleaned up parts.

Thanks for any comments/suggestions!

 

[oldballs]

I've owned a towable Mighty Mac SC1650 chipper/shredder for over 10 years now. It probably has over 100 hours on it. The only problem I've ever had were operator errors. With just routine maintenance it still works just fine. As to your problem, I'd first call MacKissic (1-800-348-1117) (the last phone # I used). Their tech support was very good as I recall.

My guess is that your belt might have been too tight.

Cheers,
Mike

 

[Stevedore]

Thanks for your reply. Nice to hear that yours has given good service for so long; their products are built like tanks.

I put the clutch back together with just a little motor oil on the bronze bushing, & everything seems much smoother & quieter now. I didn't want to call MacKissic about this problem, as the machine is still under warranty, & I didn't know how they'd react to my disassembling part of it.

 

[CalG]

Think of it as a chain saw clutch. A pump of grease up the center "every once in a while". Grease, not oil.

 

[RalphVa]

Too bad your tractor doesn't have a PTO. My Mac TPH-122 is going on 15 years. Very easy to work on. Yours looks just like the 122 but with the centrifugal clutch and an engine. Odd the replies about greasing the clutch. Never ever have I put any grease or oil on a centrifugal clutch.

These aren't made like a tank. The TroyBilt I had before it was like a tank except for the critical parts like the spacers between the hammers. For it, one had to spend hours driving the shafts through the bent up and almost welded on spacers and had to replace them all just to rotate the hammers. By comparison, rotating the hammers on the Mac is about a 15 minute job: hardest part is getting the 4 nuts and bolts off that hold the hopper in place on top.

Ralph

 

[CalG]

Too bad your tractor doesn't have a PTO. My Mac TPH-122 is going on 15 years. Very easy to work on. Yours looks just like the 122 but with the centrifugal clutch and an engine. Odd the replies about greasing the clutch. Never ever have I put any grease or oil on a centrifugal clutch.


Ralph

You don't grease your chain saw clutch shaft? Tisk. Tisk! Equipment must be serviced and maintained for best life and performance. RTFM. ;-)

 

[oldballs]

I thought I was pretty good at following maintenance instructions, but I have never greased a chainsaw shaft in 50 years. ??? I musta missed that somewhere. Guess I have to look that up.

Cheers,
Mike

 

[Stevedore]

@CalG: There's no grease fitting on the shaft or clutch hub, and no instructions in the manual regarding greasing the clutch. I did find some MacKissic instructions for an older model with a similar clutch that said to put a small amount of motor oil on the bronze clutch hub bushing before assembling, which is what I did.

Getting grease in the area of the clutch shoes & their friction surface just sounds ridiculous to me.

I do have a small chainsaw, and there's nothing in the manual about greasing its clutch either. :confused3:

 

[CalG]

A Visual on the Chainsaw procedure. No affiliation with the presenter..... ;-)

Husqvarna clutch bearing easy way to grease - YouTube

I lubed the Husky today between saw sessions.

If the clutch on the chipper is pulled off, it's easy enough to wipe some grease on the shaft.

 

[CalG]

@CalG: There's no grease fitting on the shaft or clutch hub, and no instructions in the manual regarding greasing the clutch. I did find some MacKissic instructions for an older model with a similar clutch that said to put a small amount of motor oil on the bronze clutch hub bushing before assembling, which is what I did.

Getting grease in the area of the clutch shoes & their friction surface just sounds ridiculous to me.

I do have a small chainsaw, and there's nothing in the manual about greasing its clutch either. :confused3:

I didn't think the chipper clutch would be "just like a chainsaw", only that the lubrication needs are very similar. Your original post solicited "any comments/ suggestions". I pointed out a similar component in common experience. But that appears to be less common for some than I thought.

I'll suggest that your clutch lubrication needs are similar to the Mercury Centrifugal clutches that were frequent on go-karts. ;-)

Keep the grease/ lube on the OUTSIDE of the clutch bell. It ain't rocket science!

ETA

I have the TPH 185 3pt mount pto driven, no clutch. It's a work horse for me.