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Collection, Preservation and Display of Old Lawn Mowers

Qualcast Suffolk Punch Classic - Worn pinion gear ?

There's a horrible grinding noise that seems to be coming from the roller when I engage the drive on my Suffolk Punch Classic. I think it may be because the pinion gear is worn or maybe the toothed ring that it engages with. I see that the relevant parts can be bought on Amazon But I don't have any idea about how to fit these parts. Can anyone advise me on how to do this ? Is it a simple job ? All suggestions gratefully received.


wristpin Thu, 01/10/2015

Basically you have to pull the mower apart to replace the pinion and ring gear but before you do check for wear between the roller bearings and the roller shaft, particularly if the machine is reluctant to pull back with no drive engaged or pulls back a bit and then locks.

The other thing to beware of is that there are at three different pinions, two with nylon and one with metal gears.

If you do have to strip the machine you may find it easier if you remove the. engine first before removing the right hand chassis plate as it makes the machine easier to handle and less likely to fall off the bench.

hedgelayer Thu, 01/10/2015

Thanks for that. Yes - the roller mostly locks up if I try to drag it backwards without the engine running (or with for that matter). So - can I ask some more questions ? How do I check for wear between roller bearings and shaft ? How do I know which of the pinions I need ?

All in all it's beginning to look like I have to strip the machine - could be a longer job than I thought !

Many thanks for your help. 


(2 hours later)

That seemed to go a lot easier than I thought. Got the pinion shaft out (seems it's possible to extract it from the side once you get the roller drive pulley and the holding plate off. Got the engine off, got the roller off. Pinion is obviously badly worn (see photo) and I will replace it. The toothed drive ring seemed in reasonably good nick once I had cleaned all the encrusted grease off it. The roller appears to turn freely on the spindle. I'm not sure about that bearing business - is there anything else to check now it is all dismantled ?

As for re-assembly (fingers very crossed here)... How should I grease the pinion / drive ring ? Just a liberal coating of grease all round the ring and pinion ? Or should the entire cavity be packed ? (It wasn't on disassembly). Also - what type of grease ?

Many thanks for your help on this.




wristpin Thu, 01/10/2015

Bit late now but I should have said check for roller bearing wear before dismantling by putting the machine on a level, flat surface and gently lifting it by the handle bars while observing how much lift occurred before the roller started to  lift. It doesn't take much wear to affect the mesh between the pinion and ring gear and lead to premature pinion wear due to improper meshing.

I'm a bit out of touch re the pinion types but may be the yellow colour is a clue so if you can find a yellow one with the same tooth count, go for it. I've got some pinons out in the workshop so I'll have a look in the morning.

Lubrication . I don't recollect ever seeing a recommendation but would be inclined to go for a silicone grease or even a silicon spray. Halfords do a spray for rubber and nylon . Way back when one model of Flymo had a metal pinion running in a nylon ring gear they recommended Shell Alvarnia No2 grease but I would think that trying to buy a small quantity will be nigh on impossible; we ended up having to buy a large tin which out lived the models in question!

greensleaves Sat, 03/10/2015

Hi There with regards to rear roller drive  using a plastic pinion drive  replace worn drive with new or better condition,


wristpin Sat, 03/10/2015

The question as to whether to grease or not is similar to that for exposed chains, there's no definitive answer but I would point out that Suffolk / Qualcast themselves used to put a smear of grease on the pinion and ring gear .of new machines.

The image of your pinion appears to show "blunt force" damage to the teeth commensurate with a meshing issue rather than thinned down teeth from general wear and tear so it is doubly important that both the the pinion shaft and the roller bearings are in good condition to ensure correct meshing. A new pinion may perform satisfactorily for a while but be subject to premature failure if run with worn bearings.

That series of machines under the Suffolk, Qualcast and Atco brands were subject to a number of issues concerning the rigidity of the side member and the pinion support  including serial number specific service bulletins and modification kits so there's a possibility that your machine may or may not fall into an affected group and may or may not have been modified.

EDIT. Here is the relevant bulletin. Note that Qualcast do recommend greasing.

hedgelayer Tue, 13/10/2015

Thank you both for your comments. Unfortunately I reassembled the mower before reading the latest posts. The grinding noise has gone and the new pinion (greased) appears to be working well. The service bulletin you posted on Dropbox was very interesting. It looks as though I don't have either of these kits installed. 

But the main problem now is throttle control. The throttle is incredibly sensitive. The tiniest adjustment sends the machine from idling to racing so it is very difficult to get it set at the right level for mowing. There is also a lag between increasing throttle and the engine picking up speed. The engine speed also appears to vary without adjusting the throttle. My lawn has a gentle slope. When mowing from left to right across the slope the engine tends to race. When mowing from right to left it slows almost to a stop.

There is a lever in the throttle linkage which is connected to the carb. I believe this is a governor mechanism. Could it be that this is not working ? When I gently pull the bottom of this lever out, the engine speed increases, but this never seems to happen in the course of general operation to counter the effect of varying load on the engine.

Any ideas ?

(BTW - I have so much enjoyed tinkering that, in a move which might prove foolish and which is taxing my domestic credit rating, I am now the owner of a non-running Ransomes Marquis Mk4 18" which will no doubt present many challenges - but I'll post them on a different thread !)

wristpin Tue, 13/10/2015

An image of the carburettor and its linkages will help. Assuming that your machine has the correct engine for its age it will have a mechanical governor. Within the crankcase will be a centrifugal mechanism acting on a small shaft protruding from the block. Attached to the shaft will be a lever which, depending on the exact set up will be connected to the carburettor butterfly. Again, depending on the set up the throttle cable will also be attached to the lever via a spring - the governor Spring.  With the engine running the governor will attempt to close the throttle and that action is opposed by the pull of the cable via the spring . When those two forces are in equilibrium any change of load on the engine should be sensed by the governor which should make rhe appropriate adjustment to the throttle  to maintain the desired engine speed.

If this is not happening the most likely reasons are that there is either a problem with the internal governor mechanism or, more likely, that the external linkage is out of adjustment or wrongly assembled.

Ransomes Marquis - a proper mower but with its own set of quirks and issues - enjoy!


hillsider Wed, 14/10/2015

As wristpin has said an image of the carb and governor linkages as you have them would be a great help in getting your problem sorted out, it does sound as though the linkages are possibly out of adjustment.

It will be interesting to see the kind of governor system that you have on your engine, I have only seen the older engines with air vane governors fitted but that is not to say that that they are not out there.

Quite agree about the Ransomes Marquis a project that you should enjoy.

wristpin Thu, 15/10/2015

Stumbled across a Classic Punch today and took the opportunity to take some snaps of the governor / carburettor linkages.

hedgelayer Mon, 26/10/2015

Many thanks Gentlemen. Yes, Wristpin, those photos look very similar to what I have got on my machine. 

I'm sorry to have delayed so long in providing pictures (a busy week). Pictures of the linkage are below, the last is probably the best. I'm sure you will notice the bodge job on the throttle linkage from the governor arm. I stupidly lost the original part when I cleaned the carburettor and I've no idea where I can find a replacement part (any suggestions anyone?). The wire that I have substituted is about the same length but I can't be sure. Possibly it's a bit shorter. But I don't understand how the length of the linkage would affect the problem; spring adjustment would surely maintain the equilibrium ?

The second thing I have noticed is that there is no pinch bolt fitted on the bottom of the governor arm. (Not guilty on this one ! It was like that when I got it.) When the mower is running it is possible to draw the governor arm towards the rear of the machine with my finger which increases the revs. I guess the first thing to do will be to find a bolt that fits and install it so that the arm is clamped to the shaft.


wristpin Mon, 26/10/2015

I cant remember whether the governor shaft is round and that the pinch bolt is needed to to keep the arm positioned in relation to the shaft (rotation wise) or whether the shaft has a flat or flats locating in the arm and the pinch bolt is just to prevent it falling off. I suspect the former in which case the lack of a pinch bolt explains your previously mentioned lack of governor control / response.

So, find a suitable replacement pinch bolt  - The Gateshead Mower Centre are possibly the best source for a new one  - or find a scrapper engine to rob. Assuming that your improvised link is approximately correct proceed as follows. Move the throttle spindle with the link attached to full throttle - away from the idle stop screw - and hold the governor arm there  . Then .rotate the governor shaft fully  in the same direction that you moved the arm and lock up the pinch bolt. Now when you start the engine you should see the governor arm kick back and attempt to close the throttle. Calling up for more power from the handle bar control should apply tension to the governor spring and, in turn, force on the governor arm to resist that closing action..

In the meanwhile I will dig out the machine that I photographed and measure the link.

Edit. some time later.

The link on mine is 5.5cm hole to hole.

The governor arm looks to be located on the spindle by parallel flats so unless something has gone catastrophically wrong inside the crankcase, such as someone has removed it and refitted it 180 degrees out,  it will be correctly located. Ive not to pulled mine off to check so if it turns out that the flats are only to assist with holding the spindle while setting the arm use the instructions above.


hedgelayer Sun, 01/11/2015

Thanks for that. My governor shaft doesn't have the flats that I can see in your pictures. So - found a bolt and fitted it in the manner you described and gave the machine a spin. Well there's not much grass on the lawn but it looks to me like both problems are now fixed. The throttle is less sensitive and the machine appears to be adapting to load. Many thanks for your help Wristpin.


wristpin Sun, 01/11/2015

That sounds like a satisfactory outcome. Now to avoid stale fuel related problems in the Spring drain the tank and run the engine till it stops or lace the fuel with a good dose of stabiliser and run it long enough for it to be drawn into all the jets and drillings in the carb.

hortimech Mon, 02/11/2015

Ah, you forgot the other long term storage fix. Remove the sparkplug, pour about a tablespoon of engine oil into the sparkplug hole, pull the engine over slowly a time or two to coat the internals with oil. Replace the sparkplug, pull the starter slowly until the engine comes to the top of the compression stroke. At this point, leave it alone until you need it again. When you do need it again, remove the sparkplug again and pull it over briskly, replace the sparkplug and the engine should start, but beware, it will definitely smoke when you first start it, so do this outdoors.


wristpin Mon, 02/11/2015

Well , yes and no. Posted it to another forum thread together with instructions to ensure that the points are closed.

Way  back there was a company selling dummy spark plugs that contained a capsule of anti corrosive material that once activated by pulling off a sealing tab would disperse around the carburettor , cylinder and exhaust . Before anyone points out the obvious, the  instructions were to plug the air inlet and exhaust first!