1967 ATCO F24 20" mower

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David Peters
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1967 ATCO F24 20" mower

I have just acquired a 1967 ATCO 20 " mower and the only designation I can find on the machine is a tag with F24 and a number. I have failed to find any reference to this model save for a spares manual which it shares with the D14 model. The machine works and cuts reasonably well but I started to tinker with it to see if there was anything amiss. The carb has been removed and thoroughly cleaned but not yet reset from the 'as found' settings. I have removed the head and cleaned the piston and the head of all gunge that had collected. Spark plug cleaned and the engine fired up again. So far so good. I then had a look at the chain drives and the main cutter drive chain had been adjusted to its max and was touching itself in the middle. Perhaps the chain is too long. I have read other posts about a similar problem which in principle is the same as on my model but referred to a different model. I can find no information on the number of links there should be on the F24 drive chains or the number of teeth on the drive sprockets. The cutter chainwheel assembly seems to have  21 tooth and  9 tooth sprockets. I have seen on the web  20 tooth and 9 tooth sprocket assembly available and wondered if this would work on the F24. Are parts for the F24 interchangeable with any other model of this vintage and if so which one. Unless I can find new or refurbed parts I will just have to manage with what I have got.

Any other info on this model would be welcomed

Thanks

David Peters

wristpin
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Yet again some images may

Yet again some images may make it easier for anyone to help.

David Peters
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Sorry I agree it would be

Sorry I agree it would be better with pictures. I will try and attach some

 

wristpin
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Great set of images ,

Great set of images , definitely worth a thousand words!

Like you I have failed to find a manual specifically for an F24 but what you have is an Atco De Luxe that was available in 14, 17 and 20" widths. The good news is that there were plenty around and that parts should be reasonably easy to obtain.  Certainly your machine's sprockets look quite worn and your primary drive chain appears to have a cranked link in it which I cant remember as being standard.** Perhaps someone was trying to get the last bit of use out of a well worn bottom blade and had wound the cylinder down so far that they needed to extend the chain. I've even seen the bearing housing reaction springs shortened and the shaft slot in the side plate lengthened. I digress!!

It also looks as though something may be amiss with the main plate clutch .

Anyway the attached link to a manual may be of assistance.

https://www.dropbox.com/s/nt4es8krx5hsixl/Atco%20De%20Luxe%20Owners%20Ma...

EDIT ** Poor memory, just found an old manual on which I've scribbled, Primary 52P, Intermediate 40P and Final 35P  . Counting the pitches on your image, there appear to be 52! 

David Peters
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Thanks Wristpin for the

Thanks Wristpin for the download. will print off and study. I have found a cutter wheel assembly with 21 and9 teeth on ebay. Does this have a right or left hand thread?

I attach a picture of the other side of the clutch plate. What did you identify as an issue? The worn teeth?

If I can locate cogs in better condition I will replace and get new chains They seem to be chain spec 415 like those on mopeds.

Off to search the net for sprockets

Thanks again

 

 

wristpin
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Don’t know about moped chains

Don’t know about moped chains but Atcos of  that age would usually have BS spec chain. Measure the pitch - probably 1/2” and the width and diameter of the rollers. At a guess the chain will be 1/2” x 3/16”x 1/4” or 1/2” x 1/4 x 1/4.

The traction clutch teeth look ok for further use but what you should look at is the internal ball race which has 52 loose 1/8 ball bearings  - so open it over a tray. When you’ve opened it you may find that the balls have worn a track into the centre boss and may also have worn and splayed the track in the driven plate. If they are not too worn you can add an extra ball or two to take up the slack. Rule of thumb is to pack them tight , then remove one ball. Individual balls are available from bearing factors.

While those clutch components do wear in normal use their main enemy is over tightened chains.

David Peters
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Thanks for your prompt

Thanks for your prompt response. I did know about the ballbearings but only found 42 in place. I have ordered loose bearings but I measured them as 3mm. Is everything imperial on this model?

There was no ballbearing between the clutch thrust pins so I have ordered a 3/16 as specified in the spares

can you confirm how you measure the chain size please

Does the top clutch bearing screw off  as well? Right or left thread??

wristpin
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Everything is imperial on

Everything is imperial on that machine.

Chain is specified by Pitch, the length between rivets, the roller length / width between the plates and the roller diameter. All chain is now imported from various countries such as Poland and India and there seems to be no standard pin size , so when ordering its best to order chain, and connecting links etc from one source.

Forgot.   Does the top clutch bearing screw off  as well? Right or left thread??

If you mean the clutch shaft sprocket, yes, its screwed on with a conventional right hand thread. The shaft just passes through the bearing.

David Peters
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Any tips on how to get it off

Any tips on how to get it off?

wristpin
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Any tips on how to get it off

Any tips on how to get it off?

With difficulty! If you are prepared to scrap the sprocket you can shock it off with a drift or lump hammer . Otherwise you will need a chain wrench or a homemade sprocket tool but you will also need a means of holding the shaft; Possibly Mole grips of Stillsons on a non vital area of the shaft. Sounds a bit brutal but the sprockets can be *** tight and you can always smooth the shaft out afterwards.  

David Peters
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Qualified success. Brute

Qualified success. Brute force and ignorance. The force got the sprocket off the ignorance damaged the clutch assembly

I found  something similar on e-bay from a B24 Royale

www.ebay.co.uk/itm/Atco-B24-Royale-clutch-drum-and-shaft/143605940556?ha...

Would this fit ? Before dismantling the shaft etc, how do I release the spring tension?

All I need now is to find a 9 toothed sprocket with RH thread !!

wristpin
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I found  something similar on e-bay from a B24 Royale

Similar to look at but a different diameter.

Spring. No need to remove it, leave it be. You can dismantle the clutch from the other end.