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Collection, Preservation and Display of Old Lawn Mowers

Removing Cutter Drive Sprocket on old Groundsman

Hello All,

I recently purchased an Atco Groundsman 34 (circa 1975, I think) to strip, refurbish and rebuild as a bit of a springtime project. The strip down has been progressing well, until I reached the point of removing the sprocket from the cutter drive control. Can anyone tell me how I go about removing the collar (unsure of the correct term) to allow me to remove the 2 sprockets behind it, circled in pictures below.

Also, when testing the mower before commencing the strip down, the force of the clutch engaging would cause the collar to jump from its disengaged position to engaged, is this a known issue and is there a way to stop it from happening?

Thanks for any assistance in advance.



wristpin Tue, 07/04/2020

Years since I worked on one ; and then not very often!  This illustrated parts list suggests that the collar** with the two flats unscrews and taking into account that it is "driven " I'm guessing a conventional right hand thread - but.......!

And, Yes, jumping into engagement was an issue on older worn machines . With one exception the few that I saw had Villiers Mk 25 engines.…

** H355 Sleeve nut

hortimech Tue, 07/04/2020

Everything Wristpin said, plus the thing that wears first and causes the jumping into gear is a very small pin in the splined sleeve (H353 on the parts diagram). This pin was never available as a separate spare part, but you can replace it, it just pulls out (grip with side cutting pliers and lever out). Once you have got it out, you just need something to replace it with, we used the shank of a 'pop' rivet, dressed to length with a file.


Scott S Tue, 07/04/2020

Gents, thank you so much for the information. I shall give the suggestions from both of you ago.

Thank you again.


Rocko Mon, 12/04/2021

Thank u very much wristpin, i have googled all over the place and couldn't  find anything on the groundsman 34. I recently purchased 1, running the finest. Didnt come with the trail seat, no issuse, very little to be done as in engine running fine very little rust, bit of an issue with cylinder or blade cutting fantastic all across the middle of the blade, but shy from about 5 inches from each end.  Something ill get sorted soon enogh. Just wondering If anybody might know where id find the part number k171 bracket ( front roller) i have the roller, been using a ride on for the last 7 or so years and in places on the lawns the cront guides are sitting into slight ruts and leavng the blade a bit low, tia!


wristpin Mon, 12/04/2021

I suspect that it will be from a scrap machine but worth giving Jon Cruse at the Hailsham Mower centre a call - you never know. A few years ago I had a modified pair laser cut for a customer who wanted a higher cut than that provided by the standard ones . A somewhat more recent part number is L12530 or even F016L12530

As far as your cutting issue goes, it will need a cylinder grind and a bottom blade reface. If the bottom blade is past redemption the new one should still be skimmed once fitted to the sole plate