The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers

Siezed engine - what to do now to help in the future?

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Adrian

No, not the Standard!

I've just picked up a mower I was promised in 1992 (I don't hurry...). A brief search suggests it'  an Atco 1263, though I need to check the data plate in daylight.

Unfortunately in the 34 years since I was promised it, the engine has siezed. I don't intend to do anything until I've finished the Standard, but it's ex owner is 92, so I may not have much time to sort it and show him, assuming I can resurrect it.

What's the best thing I can do NOW to help my chances of unseizing it when I get round to it? I'm pondering putting paraffin or PlusGas down the plughole (being what I have to hand) with a big sign saying "do not pull!" so I don't hydraulic lock it and letting it steep until the day I can get into it. 

Good idea? Bad idea? Got a better idea?

Forums

UTC Mon, 09/11/2026

Diesel is a popular material amongst engineers for the longer term unsiezing or preservation of engines etc.

It's a very thin oil and although perhaps not as immediately effective as say PlusGas is relatively inexpensive in quantity and readily available.

UTC

Mowing Wurzel Mon, 09/11/2026

As UTC advises,   Diesel can be used, once the cylinder head is removed.   if the piston is advanced down the bore

Assume as its a 12"  From 1963 it has the Villiers AV3 75cc engine.  We have a 14" with the same engine that was seized as left a long time and freed off.

Once freed / unseized it would be wrong to try starting it as all the ust and grit would score the bore and damage the engine,   so you would need to at least undue the big end cap and remove the piston and conrod,   I would say if this is seized the valves  at least one would have been left open for years and would need the seat  regrinding and the valve them lapped in with paste.   As a purist, any engine we buy is fully dismantled before any attempt to start it.  So would take the crank out.   The Villiers  AV3 engine is a derivative of the Villiers Mark 7  so has bush main bearings,  so the crank journals would need cleaning and as I say all grit rust and carbon from the last 63 years removing.

Best Wishes  Mowing Wurzel Paul

Adrian Mon, 09/11/2026

Thanks, UTC. I must admit I was thinking of what I had to hand but I guess if I buy a litre of diesel I can always pour the rest into the car!

BY daylight it's a 1264 - not that that makes much difference to the task!

Adrian Mon, 09/11/2026

Thanks, Paul. Assuming it's got a deflector crown on the piston, it's pretty much at TDC - does that affect what I can get in there? And am I OK just to bung some in the plug 'ole now and do it properly later? There's no reason for it to come to any harm?

While I want to give it the best chance, I have a Standard to finish first!

As you can probably tell, I am not a mechanic, so taking baby steps.