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Collection, Preservation and Display of Old Lawn Mowers

Villiers Lightweight engine ignition timing

Finally getting around to sorting out the engine of my 1960s Atco.

I've had to take the flywheel off to sort out the points so now I need to retime it.

Accord to the manual downloaded from here, the mark on the flywheel should align with "a small vee shaped rib cast on the underside of the horizontal flange of the cowl backplate".

Here's a picture of my backplate:

Am I right in thinking the vee is where my backplate appears to be cracked or should I be looking elsewhere?


Thanks for any info,



wristpin Sat, 12/03/2022

Looks like there may be some damage, but all is not lost as you can still retime from basics, but you will need to remove the cylinder head to observe and measure the correct distance for the piston Before Top Dead Centre . As you have a manual that distance should be on the spec page. Remember to set the points gap before setting the timing.

dicko99 Sun, 13/03/2022

That's what I'm guessing...

Anyway, it must be about right as I've managed to start it! I used a drill and a socket as a motogp style starter and after spinning for a while it fired up and seemed to run OK.

Unfortunately, after a minute or so the head gasket started blowing as I'd had the head off to check the bores and timing.

Do I need a new gasket or is there a chance of getting it to seal with some sort of sealant?

Have to say it sounded good when it was running with no smoke or rattles.

Also the carb is leaking a bit so I'm thinking it might need a new float valve? It's fitted with a V508C mk2. Does anyone know if the float valve is specific to that carb or will any Villiers one fit?



PS Mine is the 50cc version, I've found a 75cc head gasket at L&S, I wnder if that'll fit at a pinch?

villiers98 Mon, 21/03/2022

I believe you will need a new gasket. As the 50cc and 70cc versions have different bore sizes (10mm ) I don't think this will work .

However my book shows 505H and 507H but not 508H . According to Villiers  numbering this suggests 80cc (512 is 120cc 515 is 150 cc etc) Can you measure the bore and stroke.? The carb should be an S10/2 or B10/1 both of which were used on other models so float should be available if it has a leak

dicko99 Tue, 22/03/2022

Sorry if I didn't make it clear, it's the carb that's numbered V508C

I'm pretty certain the engine is the 50cc version as I've now obtained a 75cc head gasket and the hole for the bore is bigger as you say. However the bolt holes line up so I'm going to have a go at using this gasket before going to the trouble of creating my own... L & S think it should be OK