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Collection, Preservation and Display of Old Lawn Mowers

30" ATCO mower with 8 HP Tecumseh engine

Hi everyone

This is my first post here so please be gentle with me! I have had many old lawn mowers in the past and currently have a 30" ATCO and a 24" Ransomes Marquis. Sadly neither of them is currently running. I have had the ATCO for many years but it stopped working nearly a decade ago and I have not had the time till recently (I  retired last summer) to look at it again. It has been largely hidden under a tarpaulin. The Ransomes which I got last year ran for about a week and has not run since. I have been concentrating on getting the 30" ATCO up and running

The ignition system of the ATCO was not working and in a recent trip to the US I got a new ignition coil and capacitor. I ave replaced the oil, spark plug and air filter. It has an  8 HP Tecumseh engine. To my delight I was able to get the mower up and running; sadly only for a few days, when it stopped working.

On stripping it down I found that the flywheel key had shorn. There seemed no reason for this. I had understood  that this normally happened when one hit a rock etc. but I think it was simply metal fatigue.

There are two issues

1) I am struggling to find a replacement key. I found a pack of 10  611004 Tecumseh keys cheaply on Ebay ( a few pounds) but sadly they don't fit. I am struggling to find the correct key and would very much appreciate any help. The serial number have been spray painted over by a previous owner but I can probably clean them up if they would be useful.

2) The remains of the existing key seem to be seized to the shaft of the mower. It doesn't seem to want to come out. Any videos I have seen indicate the key comes out easily but it seems to be locked in. Possibly it is grooved and needs to be pushed out from the back. (This will require removing the points etc. so I havn't tried as yet).

I would very much appreciate any help as to the correct key or advice on removing the old one.

If anyone needs a 611004 Tecumseh key then I send you one if you contact me


Many thanks







hortimech Mon, 13/07/2015

Any chance of photo ? reason I ask is because the 30" inch is a stretched version of the 24" which is a stretched version of the 20" and they all used the same Tecumseh engine. This started with the H50 and ended up with the HH60, they were not 8hp, the only large Atco's I can remember that used a larger Tecumseh engine were the 28" & 34" that used the cast iron 9hp electronic ignition engines.

As to why your flywheel key sheered, this is probably down to the flywheel being run loose or the drive dog on the output shaft being loose. If it is the HH60 engine, the key is a straight key and should come out from the front, but it may have got pressed into the slot when it sheered, tapping it with a punch may free it, I also think that if your engine is an HH60, you require a 30884 key.

You can find a Tecumseh manual here:

wristpin Mon, 13/07/2015

Welcome to the forum.

Atco. Nothing to add other than on a cylinder ( reel) mower blade impact  per se is very unlikely to be transmitted to the flywheel key  but as has been suggested a loose component in the drive might.  Bear in mind that they key is mainly to position the flywheel for correct ignition timing ; it is clean, dry taper faces on the crank and in the flywheel plus correct  torquing of the retaining nut that hold it in position..

Ransomes . The original Marquis was made in 18 and 20" sizes and then there was a different design of 24" domestic machine called the Twenty Four.  Latterly there was and is a Marquis 61 ( centimetre) . Just to confuse matters further there were heavy duty 20 and 24" Metors and 24 and 28" Matadors.

So that's why pictures are always helpful!



Sean Danaher Mon, 13/07/2015

Hi many thanks for your swift reply Hortimech

You are almost certainly correct regards the engine; I just guessed it was a 8 HP one as the parts seemed to fit

I will try to upload some photos of the ATCO: I hope they are the right size; will upload some pictures of the Ransomes soon.

The ATCO has an old fashioned magneto/points ignition

I have found many sellers of the 30884 key, but all in the US and with  postage typically being about 4x the cost of the  key. If this is indeed the correct key I need to work out if It would be better to order a few of them.

It looks as if it will take a while for them to arrive.

It looks as if I might also need a torque wrench. Possibly the flywheel came loose.


thank you for your kind welcome

Point taken re Ransomes. I will try to publish more photos.


Sean Danaher Tue, 14/07/2015


many thanks again for your input. This looks far more sensible than ordering from the us. Wristpin however has contacted me to say that he has one surplus to his requirements and will pop it in the post!

Many thanks again you could hardly have been more welcoming!

I include some photos of the Ransomes

It is not in great condition

Sean Danaher Wed, 15/07/2015

Hi Wristpin

thanks. It has an electronic ignition, so I guessed it was fairly modern. I am working on the ATCO at present but will attempt to get  the Ransomes up and running soon.


hortimech Wed, 15/07/2015

You cannot go off having electronic ignition for the age of a mower, lawnmowers had electronic ignition before most cars !


Sean Danaher Thu, 16/07/2015


not having much success with the ATCO

The Flywheel pin arrived (many thanks Wristpin!) and I had another go at removing the old one. I removed the points assembly to get greater access. However it still refused to come out even after a spirited attempt with a punch (will try again to upload a few photos).

I reset the points gap to 20 thou as recommended and tightened everything up; aligning the flywheel as best I could (would have been only a degree or so out). I tightened up the flywheel much more firmly than before; have always been worried about stripping the threads or the difficulty of getting it off again.

I can't see a visible spark but managed to get a shock by accidently touching the spark plug. But conditions were quite bright and it's a while since I have done this (over 40 years) so I not sure how visible the spark should be.

I noticed that one of the wires from the points was a bit frayed and had been touching the flywheel when I had the points off. This was the earth connection for killing the spark. I taped this up with insulation tape and   ensured it was not touching.

Mower is not starting even turning the shaft with a high torque electric drill as I tire more easily these days when pulling a chord repeatedly. Would welcome any ideas.

Many thanks for all your input. Your interest is very much appreciated.



@Hortimech thanks, I hope to have a go at the Ransomes soon.

wristpin Thu, 16/07/2015

Certainly looks as though the flywheel has moved on and slightly scored the crank.

Key removal . Suggest grinding a chisel edge on a pin punch that is the same diameter as the key way. Then lie the punch in the key way and try to drive the chamfer under the key so as to lift it.

With the key out of the way offer up the flywheel and rotate it a bit on the shaft an see if it seats with no rocking or apparent movement between it and the crank. If it doesn't sit comfortably you can try lapping it to the crank using some fine valve grinding paste. The. Clean off all traces of paste and assemble with the new key and torque up.

i wouldn't worry too much about the colour of the spark, the fact that you got a "belt" from the HT lead would suggest that you have one?

Wiring. Looks like the wire from the capacitor has been the one grounding out so make sure of your repair and also that no stray strands are touching the points housing where the kill wire meets the ones from the capacitor and coil on the insulated terminal block.

You say that you removed the stator plate for ease of working - trust that you marked it or used existing marks when refitting it to retain correct ignition timing?



Sean Danaher Thu, 16/07/2015

Hi Wrisrpin

will have a go next week.

Grinding down an old chisel is a good idea.

Yes I did mark the stator plate. Much to my surprise I didn't have to adjust the points they were 20 thou pretty exactly when I refitted the points assembly - I had expected to readjust them.

I have taped up the points ground lead and ensured they are not rubbing.

I will keep you posted. Many thanks for your excellent advice and help with the flywheel key.



Sean Danaher Sat, 25/07/2015

Just to keep you updated I have run out of time this week and will be away on holiday for the next two weeks so it will be August before I have time to look at this again