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Collection, Preservation and Display of Old Lawn Mowers

New member requesting info on my Atco

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Hello. I have just come across this old Atco and purchased it as it reminded me of the mower I used as a child. It has great compression and seems to want to start, but has no/weak spark. Is there anything else to know about the engine? Should I be using a lead substitute in the fuel? I have pretty good mechanical skills having rebuilt several modern engines in cars but have not experienced anything this old ! My plan is to preserve and use it rather than a full restoration. 

 

Any help/tips really appreciated.

 

Thanks,

 

James

 

Forums

Darren - FAC Wed, 26/06/2019

Hello James, 

I'm an Atco fan myself, for the same reason as you, so I like your mower. I've just bought a couple in the last few weeks, although not quite as old as yours, I think. 

I'm sure some of the knowledgeable and helpful members of the forum will be along soon to offer some suggestions. With both of mine, I wasn't getting a spark either. With one, cleaning up and adjusting the points got it working, but with the other I've reached the conclusion (with the guidance of members here) that it's the coil / condenser that needs replacing. 

Best wishes, 

Darren

P.S. Welcome to the forum. 

JHock Wed, 26/06/2019

Thanks Darren. Is there a manual available for these mowers? I will check the points later. Did you add lead to the petrol of your mowers? Also, I am going to remove the carb and whack it in the ultrasound tank I have; do you need to seperate it, and if so how do you recalibrate it when placed back on the mower? I am a bit lost without a decent manual :) 

 

Thanks again,

 

James

wristpin Wed, 26/06/2019

Ultrasonic cleaners are great but to get the most benefit from the process the carburettor must be dismantled.  However, the Zenith carb on your engine is so simple that an aerosol of carb cleaner will possibly achieve a similar result. The most likely area to cause you trouble is the slow running tube which, if badly blocked,  can resist even the u/s treatment.  Fortunately slow running tubes are readily available at modest cost.

As far as manuals go , the owner handbooks of the period were fairly comprehensive and should guide you through carburettor and ignition servicing, some even covered valve servicing. While on that subject , decently sealing and adjusted valves are the basis of a decently running engine. On an engine with an unknown history, time spent at the outset on a valve job can save a lot of time spent fiddling around with the carburettor and ignition.

 

JHock Wed, 26/06/2019

Oh that sounds interesting. I have hand lapped valves into a 5 cylinder engine so think I could manage the job. Are you talking about making sure the existing valves are lapped, or having new valve seats and valves fitted? Do you know where I could find a manual for this engine/mower? Thanks for the help so far. 

wristpin Wed, 26/06/2019

I'm guessing that your 5 cylinder engine is Over Head Valve  or even Overhead Cam. The iron block Suffolk Iron Foundry engine on your Atco is a fairly crude side valve but it does present some issues not present on the above.

For example the valve seats are cut directly into the cast iron block and the valve clearances are adjusted by grinding metal from the valve stems or cutting the seats.

This may help with your original question re the carburettor.

https://www.dropbox.com/s/uhq64tkaa0zxpn8/Zenith%20carb0002.pdf?dl=0&nb…;

I'll see what I can dig out to help with a valve job.

JHock Thu, 27/06/2019

Thanks, that looks just the job for servicing the carb. I will see how far I can get with it later on today and make a quick video with a few more questions about some of the parts. 

Darren - FAC Fri, 28/06/2019

Not meaning to hijack your thread James, but I was interested in something Wristpin said above. There was mention of using carb cleaner, and as I'm a fan of "liquid engineering, I wondered what the easiest way to go about this would be. My 14" seems to run nicely at the moment and I'm wary of tinkering and making it worse, but I think a simple clean up of the carb would probably be a good idea.  Would I need to dismantle the carb completely?

Best wishes, Darren 

wristpin Fri, 28/06/2019

The cleaner that I use is for dismantled components . Various American sites talk of “ Mechanic in a Bottle”  and Sea Foam which are added to the fuel to clean the system “ on the go” but I have no experience of either.

JHock Fri, 28/06/2019

Ok this is where I am at. Carb stripped and currently in the ultrasound tank with some specialist carb cleaner. New fuel line ordered. No spar, so stripped down to the points? Anyway, I have never seen anything like this before, so need to know what to tinker with/repace/test, in order to get a nice spark. 

Best wishes james. 

 

 

wristpin Fri, 28/06/2019

You have quite an early one there  Would the carb by any chance have a round ball float?

Also, is it just the image or is the crankshaft keyway damaged?

Just make sure that the contact breaker points are clean and correctly set. In the case of the early magnetos that would be to 20 thou. You should find the setting figure embossed into the flywheel or the removable inspection window.  Interestingly, those old fabric covered coils seem to survive better than the later "plastic" covered ones. Unfortunately the same cant be said for the condensers which do deteriorate over time. 

JHock Sat, 29/06/2019

Hi, yes its a ball float in kind of  rounded cylinder, rather than perfect sphere. I think I have some imperial feeler gauges so setting the gap should be ok. The keyway is fine by the looks of things. How old do you think we are talking? I was guessing 1950s? 

hortimech Sat, 29/06/2019

It cannot be before 1965, because that is the year that Qualcast bought Atco and before that, Atco didn't use Suffolk engines. This was because Qualcast owned Suffolk and Atco used Villiers engines.

The engine is interesting because I thought that type of ignition system and carb had been replaced in the early 60s, perhaps it was fitted with a service replacement engine at some point ?

wristpin Sat, 29/06/2019

So it has a cylindrical float with slightly domed ends and the needle fixed into it? If the slow running jet is screwed in with a visible screw driver slot, the carb is a Zenith 13TCA dating from 1957 .The fuel inlet is is on top of the carb body via a screwed in union with Banjo fitting.  

In 1964 they switched to a 13TCA-2 with a push in slow running jet and a cast in fuel inlet pipe, 

The very early carbs  13TA,  1954-1956 had a completely spherical float with no needle but a  needle valve capsule screwed into the under side of the carb top.

JHock Sun, 30/06/2019

Thanks a lot for the information. Maybe the mower had the engine retrofitted? Its a bit annoying that it is lacking an ID tag anywhere. 

JHock Sun, 14/07/2019

Good afternoon. I have finished stripping down and rebuilding the mower and i still have no spark. Points have been adjusted and cables checked. Nothing obvious is wrong. Im guessing the main coil is dead and generating no charge. Any advice on a modern replacement part to get me up and running ? Also does anyone know the base settings for the carb after reassembly? Thanks. James 

wristpin Sun, 14/07/2019

Find a mower or motor bike place that can test the coil - leave it on its armature. If they can do a proper test on the condenser , even better. If the coil tests out ok and they cant test the condenser a new one is far cheaper than a coil and may solve the problem. That stator plate has a 15mm square laminate for the coil and most later plastic covered ones have a 9mm square. You can still get the correct coil  - at a price, £58! 

 

 

 

JHock Sun, 14/07/2019

Ouch ! I just want to get the mower working so I can use it to get a lovley striped lawn. I have been working on restoring my lawn for a couple of years. If I have to spend out on a new coil I will, although I would much rather just replace the condenser. I am going to get it into the workshop and on the bench tomorrow for a session with the multimeter ! If I can get it running and cutting well this summer, I will treat it to fresh paint and new gaskets etc in the spring. 

wristpin Sun, 14/07/2019

The multimeter is better than nothing but does not stress the coil to detect "iffy" insulation and depending upon what one reads, is not really much good for condenser testing. See what readings you get off the coil primary and secondary.

 

JHock Mon, 22/07/2019

Sorry for the delay - DIY took priority for a while. So here are my findings:

 

1) No continuity in the spark plug lead.

2) Condenser seems ok from the basic charge/discharge test carried out on a multimeter.

3) Readings of coil found as follows:

Spark plug end of coil (secondary) to larger wire coming out of coil to condenser (primary) has 3.93 K ohms of resistance.

Spark plug end (secondary) to the small cable going to earth (no idea what this is)  has 3.82 K ohms.

 

There is continuity between the small wire going to earth and the large wire coming off towards the condenser

.

 

Hopefully someone can shed some light on this for me. As far as I can tell, the coil might be ok and it is just the bad HT lead that needs replacing?

 

Thanks

 

James

wristpin Tue, 23/07/2019

Obviously you need to sort out the HT lead

These are the readings from a new old stock coil.

HT tab on the coil to uninsulated ground wire, ie coil secondary 4.14

From the uninsulated ground wire to the insulated coil primary wire. 7

I actually took the readings from two unused new old stock coils and the readings were identical.

JHock Thu, 25/07/2019

Hi all,

My coil has continuity between the earth/naked wire and the primary which is no good at all. Any idea where to get a new coil? Best wishes James

wristpin Thu, 25/07/2019

It should have continuity, what is the resistance?

EDIT. Have I misunderstood , are you saying no resistance? If so that is not what you need. Villiers Parts sell new coils - at a price!

JHock Sun, 18/08/2019

Just got back from holiday. Have a new meter now so will repeat my readings and get back to you.