OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Rover 45 clutch noise

Hi guys,

Thanks for a great forum.

My Rover 45 started getting noisy (like a loud whirring / screaming from the clutch area) when the clutch was engaged a few weeks back, and seemed to get a little bit worse recently. A video of the noise it was making can be seen at the following link:

http://1drv.ms/v/s!Aqqs5SaUjwc-pv0r1GBEVjBXslo8ww

This morning I tightened up the grub screws holding the clutch to the shaft, and it "seemed" to stop the noise at the time. Next time I ran it though (this arvo), the noise was back. I tried tightening the grub screws again, but one of them just kept on spinning, obviously not great. Decided to pull it all down and take a look. Removed the engine (very easy - thanks to DeeJay's video - cheers) and the clutch slid off with no dramas at all. I've attached some photos of what it all looks like.

I'm guessing you'll want me to pull the clutch cone apart for more photos?

Also, I'm assuming I will need a new "key" for the engine shaft, a new grub screw to replace the one with the thread issue, and perhaps even a new "engine side clutch half"? Anything else I should be adding to the list? Very happy to take your advice, as I don't really know what I'm doing

Cheers,
Damian

Hi Damian,

I think that your clutch may be out of adjustment with heat witness markings all over the black plastic thrust pad.

I'd say the there was still pressure on the pad while the cutter was running, but when correctly adjusted there should be none whatsoever.

Your key steel can have the burs filed off and reused but the issue is your clutch that isn't solidly attached due to one set screw being loose.

Now the next issue is whether that your clutch half is any good or is it due for replacement.

With your set screw not being able to be tightened you'll find that the thread will be stripped in the ally housing and thus would require a helicoil inserted to resolve the issue, but if the housing has been flogged out over time as they will do, it will no longer run totally true and as such the whole drive line has increased unbalanced stress placed upon it.

I would place the clutch half back onto the engine shaft and tighten the set screws, then take the spark plug out and pull the recoil starter rope slowly but evenly and note whether the clutch body rotates truly or wobbles left and right during its rotation. If it does wobble the a new clutch half is in order to resolve most issues along with a new thrust pad.

Cheers,
BB.

Evening,

Thanks for your help so far BB - very much appreciated indeed.

To answer your question: I filed back the key and placed the clutch onto the engine shaft, securing it with the screws (well, the one that still bit). With spark plug out, pulling the starter slowly shows the clutch with some wobble in it, perhaps 3-4mm of wobble.

I then took the clutch off and pulled it apart, finding the cork in very good condition. I cannot seem to remove the thrust bearing though, and turning the bearing by hand, it spins quite well, but is rather noisy. Should I be able to remove it easily?

My thinking is I will need a new 3/4 inch (that appears to be the diameter of the engine shaft) clutch half, new thrust bearing, new plastic thrust pad? Anything else I would need?

I'm still not really sure where my original 'screaming' noise would have come from, perhaps the thrust bearing?

Cheers,
Damian

Hi Damian,


I will say that you'll require a new Clutch half and I'm pretty sure it would've originally been fitted with a 5/8 unit if the original engine was still fitted to it, but yours seems to have probably been replaced with one of the same type that has no throttle cable connected to the handle bar controller and also fitted with an unusually supplied 3/4 size PTO shaft.

The only way to get the thrust bearing safely out is to use a 3 jaw expanding end slide hammer.
Failing that you can use a pin punch and poke it in through the engine PTO shaft side of the clutch and gently tap it out moving the punch around the inner race while tapping it softly. No hard blows here as you'll stuff it up. Generally you should never apply pressure on the inner race but in this instance you have absolutely no choice. Technically speaking these bearings were a one of use and designed to be thrown out and replaced at the same time as the clutch half body.

Once you have the bearing out successfully soak it in petrol to thoroughly clean it out and then blow compressed air through the very slim openings around the inner race to completely dry it out.

Here comes the hard part. Find a small syringe (Chemist) and fill it with grease and squeeze grease in through those slim openings. Push the inner race inwards so it runs smoothly and work the grease around. You won't require massive amounts that's for sure.

Confirm that engine PTO shaft diameter first before you buy a new clutch body as they ain't cheap any more.


Cheers,
BB.

Thanks mate. Great instructions.

I'll have a go at getting that bearing out tomorrow night. If I take a 5/8 socket, it doesn't fit over the engine shaft, whereas a 3/4 socket does. Measuring the shaft diameter shows that it is .75" in diameter. So I think I should get the 3/4 size clutch body ?

No need to buy a new thrust bearing ?

Cheers,
Damian

Hi Damian,

Well at least we've got the PTO size down pat. 3/4 size was generally used on Honda / Asian power plants, but if that's what it is then get it.

Thrust bearings are usually not required to be replaced if retrieved successfully without damaging them and definitely not on a machine that new as yours.

You will though require a new thrust Pad.

Cheers,
BB.

Hi BB,

Received the new parts this morning and installed them successfully. The clutch body now spins truly without wobble, and the grub screws are in nice and tight (though, not TOO tight...). I believe the "screaming" noise has certainly been reduced, however I do feel as though it's still probably noisier than normal.

I have tried running the reel at a decent speed using an electric drill, to see if the 'screaming' noise was coming from the reel side of the equation, but it does not make the noise in that scenario. Only makes it when the cutter clutch is engaged. Everything in there looks to be in perfect condition though, so given the noise seems to have been reduced, I'm tempted to just leave it be...

Hi Damian,

Just a small question, when the cutter is running is there a small gap between the clutch fork and the back of the thrust pad, say about half a millimeter ? thus no pressure being put on the clutch cone by the thrust pad ?

Cheers,
BB.

Hey mate,

Yes there's a approx 1mm gap between the fork and the thrust pad when running, no pressure on it at all. I'd seen you post about this on another thread I think so I purposely adjusted it as such

Cheers,
Damian

Hi Damian,

How tight is your primary cutter chain as many people set up the chains and then put the chain case on and only then adjust the reel downwards for the blade set which then over tightens the primary chain without knowing.

So how is it ?

Cheers,
BB.

Hi BB,

Attached is a photo of the chains. Perhaps too tight? Not sure how tight they should be, there is a bit of give, but there could be more I think.

You are spot on too - I did adjust the reel after setting the chains. Did not even think twice of it. I can try loosening it in the morning to see if it improves the sound?

Thanks for your continued assistance - your expert help is very much appreciated!

Cheers,
Damian

I feel there are at least two possibilities here:
[1] If the noise occurs only upon engagement of the primary clutch,
then the issue will be post-clutch.

Changes in reel set - alone - will produce significant changes in sound.

[2] If the sound only occurs with dis-engagement drive, then the issue will
be within the primary clutch.

If the thrust pad has sufficient free play, then the most likely cause will
be a dry or failing thrust bearing located within the inner clutch body.

Please advise when the noise occurs: disengaged or engaged.
I feel Mod BB needs this info to advise further.

Hope this helps.
-------------------------------
Jack

Hi Jack,

The noise only occurs upon engagement of the cutter clutch. I've actually just replaced the inner clutch half including new greased thrust bearing (BB correctly advised me I didn't need to, but I bought one anyway in case) and thrust pad.

I've really enjoyed playing with the 45, it's nice and simple and very well designed.

Cheers,
Damian

HI Damian,

I feel that the secondary chain (cutter to Land Roll Clutch) is way too tight and this will ad strange noises into the equation.

It's a bit of a fine art to adjust that one and the rear roller chain simultaneously, but for that reason the land roll clutch is adjustable in two planes, up and down while also left and right. I would just loosen the two nuts ever so slightly and then using a pin punch on the top edge and tapping the slider downwards very very lightly this way you'll achieve a slight amount of chain deflection which is all you'll require.

At the moment it is stretched rather tightly and this would be placing a lot of lateral load on the two bearings concerned which is quite unnecessary.

As Jack has allured to that the set on the blades will have a certain sound that will change if the set itself is altered. (Thanks Jack)


Cheers,
BB.

Good morning BB,

Again you are spot on - I loosened the Cutter to Land Roll chain and that has basically eliminated the noise.

All in all I think this has been a very fruitful exercise - identifying and replacing a suspect clutch body (with a stripped thread), a damaged thrust pad and not to mention learning a whole lot along the way.

I would just like to say thanks for all of your help and happy mowing.

Cheers,
Damian

Hi Damian,

Glad we got to the bottom of it.

A picture is worth a thousand words isn't it ?

Replacing the clutch half was a good precautionary thing as in time with it running out of balance it will induce stress fractures into the rails. I always suggest that clutch bodies need to be replaced sooner than later as it's a cheap fix compared to a damaged rail / rails.

Happy mowing !


Cheers,
BB.


PS. Check out the photo below and see what effect an unbalanced clutch body will result in...................................................

Yep that one has some damage!

Snuck in a quick mow this morning, picture attached for your viewing pleasure.

Cheers,
Damian

Gotta Love the Rover Reds !!

I'd have one if I found a good one but they are pretty thin on the ground as not that many were made and sold.


BTW Damian yours is the very last variant of the Model 45 before production ceased.

Cheers,
BB.