Oxford Allen Autosythe Villiers engine won't turn 360 degs

[vhgmcbuddy]

Hi,

Just joined the website today. Good chance I’ll hang around as I have the following:
Oxford Allen Autosythe (problem to follow)
Howard rotovator (engine off, seized, needs strip down)
J.A.P Model 5 (used to drive cider press, under plastic sheet, not run for 4 years or more).

Anyhoo, the problem that is concerning me at the moment is with the Autosythe. It was always a reliable beast. Left for years covered up in the barn, dragged out every now and then and it always started. Last year, I dragged it out and when putting the starting cord on I realised I couldn’t turn the engine 360 degrees. It feels as if there is something stopping the piston, presumably at the the top of it’s travel. I’ve checked the knife its drive mechanism over to make sure there was anything there in the way and I’m pretty sure it’s something in the engine.

IIRC, the engine is a C25 four stroke. Does that sound right? Can find out for sure in the daylight tomorrow. Have a piccy to upload too.

Basically, what’s the most likely cause and how do I go about confirming and fixing it?

[andyfrost]

Hi , C25 is a fourstroke , it could possibly be a stuck valve , best thing is to remove the cylinder head and have a look.

Andy.

[vhgmcbuddy]

Thanks for that. I had the phrase stuck valve in my mind but wasn’t sure it was a thing.

Any guides online on removing the head and checking the valves and putting it all back together again?

[charlie]

Removing the head is fairly straight forward after removing engine cowling. Valve clearances should be .006″ inlet and .010″ exhaust.

[vhgmcbuddy]

Well, YouTube has failed me (brings up blackhead and cyst removal ! )

Any links to manuals or step by step guides. Not found anything myself so far.

[charlie]

The C25 is very similar if not the same as the older Mk25 Villiers.
Remove fuel tank and engine cowl; undo cylinder head bolts, remove cylinder head. To access valve springs remove cover on side of engine located below inlet and exhaust. To remove valves compress spring and remove collars, this can be a bit of a fiddle. Re-assembley is reverse of dismantling; to set valve clearances check exhaust with inlet fully open and check inlet with exhaust fully open before fitting valve springs. If valve clearance is too small end of valve stem can be ground or filed to increase clearance, make sure end is square and flat. Meetens may have owners manual instock, this will give details of spare parts and routine adjustments, but not a full engine rebuild guide.

[vhgmcbuddy]

Charlie,

Thanks for the advice.

[Author]

Posts