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Collection, Preservation and Display of Old Lawn Mowers

Identification of year of mower, info on replacing cutter cylinder


i have an Atco Royale 24 inch cut 4 stroke, there are no plates with id nos on, to help identify the year ect, it has a Tecumseh engine, metal throttle lever on right side of handle, metal clutch lever on left side. I have taken the cylinder and bottom plate off to have them sharpened in the uk. I have some written info and pictures of the removal process, Ie chains bearings nuts bolts ect. I am trying to find a u tube or manual that gives me a step by step guide as to replacing the cylinder, bottom plate, bearings and spacers. I have a basic engineering knowledge but am aware the mower needs to be re built correctly and set up correctly. Any information or help is appreciated,

hortimech Thu, 23/03/2017

First are you sure it is a Royale ? I think you actually have an Atco 24HD, not that it makes much difference when it comes to rebuilding your machine.

A few pictures will confirm it one way or the other.

I don't know of any video's and there wasn't a repair manual (unless Wristpin has one), but as you have stripped it down, you should be able to reassemble it.

You say you have removed the 'bottom plate', if this is the thing held to the bottom block with all those screws, get it back and refit it to the bottom block, the blade needs to be skimmed whilst attached to the block.

Refit the bearing assemblies to the cylinder, ensuring that washers are fitted correctly, thick washer first, then the shim washer. The clamp screw on the aluminium bearing housing should be left loose at this point. Fit the cylinder assembly to the chassis and firmly tighten the mounting bolts. Loosen off the adjuster bolts, then refit the bottom block assembly, ensure that there is plenty of clearance between bottom blade and cylinder.  Refit the sprocket etc to the cylinder drive end and firmly secure, you can now tighten the clamp screw in the aluminium bearing housing. Adjust the bottom blade to cylinder contact, do this slowly and do not set it to have a hard contact, they should just brush one another and cut thin writing paper. You can now refit the delivery plate and chains etc.

Any questions, please ask. 

Timecutter Thu, 23/03/2017

Hi hormitech,

thanks for the response, regarding the model, I may be assuming because this machine has a seat and roller that can be fitted, did the HDR model have this?. Regarding the bottom blade, I could not get the blade off as the twelve screws were immovable, so I took the whole frame off took it to uk with the cylinder and it was sharpened/ skimmed by the same guy who sharpened the cylinder, if you have more thoughts on that please let me know. I appreciate the info you have posted, I will make a start shortly on the rebuild and will contact you again if needed. Thanks again.

best regards.



hortimech Thu, 23/03/2017

Yes, the earlier 24 inch HD could be fitted with a towed seat. All the Royale's I have seen had a Briggs & Stratton engine. You say yours has a Tecumseh, is this painted green, with a round airfilter, the cover of which is retained by two small screws, also is the muffler a rectangular shape, retained by two large cheese-headed phillips screws ? If so, you do not have a Royale.

A picture would confirm just what it is, if it is a 24 inch HD, it will be from sometime between 1970 - early 80s. The Royale replaced the the HD in the early 80s, the main differences being the engine and the replacement of the clutch lever with a bail arm across the handle bar.


wristpin Fri, 24/03/2017

Echoing what Hortimech says, your description of the controls makes it "pre Royale". As far as I know, Atco never published a workshop manual as such - just service bulletins to cover specific issues. H's reassembley description is fine but a deeper understanding on the reason for the aluminium alloy  RH bearing holder with the pinch screw will save you a struggle . As said, when assembling the RH bearing the heavy "dirt excluding" washer goes onto the cylinder shaft first followed by the shim or "distance washer" then the bearing. At that point it pays to make sure that the bearing is a reasonably tight fit on the shaft and will stay in position and not "float". If it is a sliding fit a few equally spaced centre pop dimples around the shaft will raise a little metal and keep it in place. If that smacks of bodgery a drop of Loctite and let it set. Then clean any corrosion from inside the alloy housing and wipe with just a smear of grease before pushing it housing right over the bearing.

Why all that messing around? Well one reason for the sliding housing is to "reduce the length" of the cutting cylinder and make it easier to refit into the chassis. Once positioned, support the RH end either by just engaging its three hex head screws or inserting a couple of taper punches while you re-ft the sprocket and drive sleeve etc at the LH end and do it all up tight to positively locate the cylinder. Then you can evenly do up the screws at the RH end to draw the alloy housing snug against the chassis side plate before tightening the pinch screw to grip the bearing which should stay in place against the shoulder of the cylinder spindle. That way you don't have to fight the cylinder back in and nothing is under strain when done.

Again as said, trailer roller seats were available -  early machine just had a normal clevis drawbar  but later ones had Autosteer, a parallelogram linkage which steered the roller under the seat for more accurate tracking when going round curved flower beds etc. Great in theory but in practice could lead to a feeling of instability.

Finally, here's an image to match H's description of  the Tecumseh engine used for many years and pre-Royale.

Timecutter Fri, 24/03/2017

Hello wristpin,

thanks for the info and picture, yes that is the mower I have, so now I now it's a 24hd. The advice about fitting is welcomed, I have RS shielded bearings to fit, does that mean I can forego the dirt excluding washer or not?, also it does not look like there are any shims when I dismantled.

best regards.



Timecutter Fri, 24/03/2017

Hello hortimech, 

apologies for incorrect spelling of your name last time, bloody predictive text is my worse nightmare.

i can confirm the mower is a 24 hd your description fits all, I have had some info from wristpin, from the advice you have both given I should be able to refit then cylinder, I am aware there may not be the correct parts when I dismantled as I explained to  wristpin there does not seem to be any shims.

thanks again for all the help and assistance.


best regards.




gtc Fri, 24/03/2017

I see that you have asked a similar question in a different part of the site. Not considered good forum etiquette.

Anyway, I posted a link to engine dating in your other thread.

wristpin Fri, 24/03/2017

You should not ditch the dirt excluding washers as not only do they protect the bearings but also locate the cutting cylinder . Also,  you really need those distance washers ( that was Atco's name for the shims) as they maintain a clearance between the dirt excluding washers and the stationary outer race of the bearings. As far as using sealed bearings goes,  just remember that the lubrication of the bearings is then limited to whatever the manufacturer included when they were made.

hortimech Fri, 24/03/2017

You should use sealed bearings, there is no real way to lubricate the bearings apart from giving them a squirt from an oil can and I don't think much of the oil would actually reach the bearings. If you use rubber shielded bearings, you can 'pop' one of the seals out, pack it with grease (but don't over do it, leave some space) and then refit the seal.


Timecutter Fri, 24/03/2017

Hello GTC,

thanks for the info you sent, excuse for posting twice is, I joined the club two days ago, I looked for any info as to posting where why how ect and could not locate any info, I initially put the request on the general site, then realised I needed tech info regarding the fitting.