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Collection, Preservation and Display of Old Lawn Mowers

Ransomes 20" Marquis

Hello every body,

My name is Julian and I'm a Classic Car French mechanic, ,based in Normandie (France). To be kind with one of my customers, I accepted to have a look at his Ransomes 20" Marquis lawnmower which didn't run for the last 10 years ! The series number is FQ 01 393.

Thanks to the documents proposed by your club, I identified this 20" Marquis as a Mark 4, with a Villiers A15 engine (see pictures attached).

First question : Am I right ?

Second question : Do I have any chance to purchase any parts for this mower, as a carburetor service kit, a capacitor, a contact set, etc... ?

Kind regards,



The Colonel Mon, 25/10/2021

Hello Julian,

Afraid I can't help with the lawn mower but can we have a pic of your Land-Rover please - looks very good from what can be seen.


Allister Mills Tue, 26/10/2021

Good evening guys,

Thank you for your replies.

So "Wristpin", you confirm that this mower is a Marquis Mark 4 and my engine an A15 Villiers ? I spent one hour on this mower and I can already affirm that the ignition is an electronic one. Anyway, I have no spark for the moment. I tried to measure the compression by using the handle. 4 bars, no more. Is it correct ?!? It looks weak, isn't it ?

And for you "The colonel", here are 2 pictures of my very early 1959 Series 2 LWB Land Rover (#161900030)...

wristpin Tue, 26/10/2021

I can’t really comment on your compression reading as I don’t often take a reading, just judge it by feel . The chances are that as the machine has been standing for 10 years the valves may not be seating properly and it will be worth removing the cylinder head and valves and giving it a de- coke.

Ignition. I have found that those electronic units need a good hard pull to raise a spark. Take the plug out, squirt a bit of light oil down the bore and leaving  the plug out see if a good strong pull will find a spark. If you still can’t raise a spark  you may have to consider a new coil module  - did you get the list of potential parts suppliers that I sent by private message?

I only sent you a Mk4 parts list because that’s what you said you have - does the machine not have the  Ransomes ID plate on the right hand chassis side plate?

Allister Mills Wed, 27/10/2021


I did not receive your PM but to be honest with you, I don't know where my PM are supposed to arrive !!

The only plate seen on the mower just says "Ransomes 20" Marquis, FQ 01 393"...

And but the compression, it's not easy for me to have an idea just by feel as I'm not used to work on these machines !!

Thanks for the advices

Allister Mills Wed, 03/11/2021

Good evening Gentlemen,

The VILLIERS B10 carb is now completely dismantled, cleaned, "ultra-sounded", and almost ready to be overhauled. The pilot jet looks firmly screwed in. I'm scared to break it if I insist...

Moreover, I carefully read the VILLIERS B10 Engine manual and there is nothing about the ignition system (timing marks, wiring diagram, etc...). Where may I find these informations please ?


wristpin Wed, 03/11/2021

The A15 manual that I have posted gives the ignition timing as 1.62mm Before Top Dead Centre.  ***

Pilot jet . Try boiling the bottom half of the carb in a pan of water for five or ten minutes in the hope that the expansion of the alloy will free it off.  Failing that just squirt carb cleaner down it and hope that you can see it emerging in the base of the float bowl. 

*** Edit. After posting my reply it occurred to me that you have said that your engine is the later one with electronic ignition so I'm guessing that the timing is not user adjustable and is automatically adjusted by the electronics.

Allister Mills Thu, 04/11/2021


You're right about the ignition timing. 20° BTDC or 1,62mm. But as you said yourself, my late A15 VILLIERS engine has an electronic ignition and it's perhaps not possible to adjust it.

Concerning the pilot jet, I will try to carefully unscrew it and I will see !

Are you please able to produce a scheme showing the wiring diagram (which should be very very simple) between the spark plug, the ignition switch, the electronic unit, etc... ? Here is my email address :



wristpin Thu, 04/11/2021

Wiring.  HT lead direct to plug. Presume just one “ low tension” connection on the electronic unit - that goes to one terminal of the on/off switch . The other switch terminal to earth/ground. Sometimes that switch terminal has a permanent soldered wire then wrapped around its mounting spigot which provides the  ground  - if you are doing any painting of the cowling, just provide some bare metal around the spigot and also one of the cowling mounting bolts so that with the switch in the  “make” position the coil is grounded - engine stopped. Switch “ open” , coil not grounded , engine running.

Allister Mills Sun, 07/11/2021

Good morning Wristpin,

Thank you for the wiring informations. Simplier is not possible !

A last question : what about the settings torque for the cylinder head bolts and the flywheel securing nut please ?

I carefully read the A15 Engine manual and didn't find the answers...



PS : some pictures after a quick restoration...

wristpin Sun, 07/11/2021

How did you achieve that degree of bling to the carb?

Torque figures. Strange that the A15 manual is silent . However as it’s evolved from the F12 I go with those, Flywheel 30 ftlbs, head 12, big end cap 8, end cover 9.

You may find this useful. When the carb is back on the engine with the exhaust and the engine cowling back in place, machine on the ground , it’s not that easy to find the throttle stop screw ; and with the engine running to keep a screwdriver on it to make the 1/8 turn adjustments in conjunction with the mixture screw to get “ perfect tickover and smooth acceleration”. I take  a 1” length of heat shrink tube in a bright colour, slip it over the stop screw and warm it up to grip the head but not so much that it closes the open end.  When it comes to adjustment time you can poke a long thin screwdriver in behind the exhaust  and the open end of the heat shrink will guide it on to  the screw and keep it engaged into its slot and aid adjustment despite engine vibration. 

Allister Mills Sun, 07/11/2021

Thank you for the torque settings. I will apply them tomorrow morning. Thanks too for the tips about the adjustment of the throttle stop screw ! if every thing goes right, the engine should run tomorrow...

Concerning the carb's degree of bling :

1st step : ultrasound bathing

2nd step : sandblasting

3rd step : application of Rustol by Owatrol (spray)

Allister Mills Sat, 20/11/2021

Hello Wristpin,

Thanks to you, a Ransomes 20" Marquis Mk4 is back on the lawn.

Thank yoy for your advices and your help.

Kind regards,