Hello again,
Right, next check!
I have bled the oil pump and wanted to check the oil pump “piston” stroke.
I have been turning the engine over by hand with spark plug out, but the oil pump “piston” does not move backwards or forwards at all.
I have tried this with the oil pump cable pulley pulled to the full throttle position.
Does that seem normal or do I need engine speed to see the oil pump piston move, or does something else need checking?
As always, many thanks for any insight!
Mike
 

I appreciate that there probably isn't a wheel for manual bleeding on that oil pump but, on the ones where there is, I can see the piston move when turning the wheel. I would therefore expect to see the piston move when kicking it over.

If it transpires that yours needs a clean and/or rebuild, then I do have contact for that service here in the UK.

If there is a problem… hope it is the pump and not a problem with the drive from the rebuilt engine.
If you could share your contact, would be grateful.
Thanks,
Mike
PS - mine doesn’t have the thumb wheel.

You'll have to turn it over a lot to see it move.  A whole lot.  Without the thumbwheel, engine running it the best way.

Run on premix if you're not sure about the pump.

Did you rebuild your oil pump?

Thanks for the replies.
”turn over lots if times”…. Yes you’re right. Tick over will be >1000rpm and I’ve seen youtube showing the piston movers relatively slowly. So would need lots of by-hand turns.
I will restart uaing premix and auxiliary fuel tank, so pump to carb pipe can bleed through. That pipe is clear so will be able to see what’s going on.
The pump has just been removed and refitted during the engine rebuild (which wasn’t needed due to seizure).
Was just looking to check the basic settings.
When (hopefully) running, will watch it the pump and pipe, check the settings and hopefully all will be good.
Thanks very much,
Mike
 

When spinning the engine from the magneto side, are you spinning it clockwise or counterclockwise?

Did the engine seize from lack of oil or something else?

Perhaps spin the motor with a good drill with plug out via the mag nut spinning it anti clockwise looking at it.
Get someone to hold the drill & observe the pump piston while holding the cable out or better still use two fingers to depress the cable roller to give the pump piston & plate plenty of room to move.
One thing i just thought of, on those later pumps with a threaded pin that the cable roller bears against--has the threaded pin been left out. If so there'd be a small hole guessing a 3mm threaded hole visible.
If that threaded pin is missing, then the return spring under the cable roller tries to push the cable roller up as the shaft moves on the up stroke & can then hold it up & stop down movement.
Jeez sorry that sound complicated--but i know what i mean lol.
In saying 'that' 'DEET' is man for pump advice--& to tell me off if i'm steering you wrong. All good.

Thanks all for the further comments and suggestions.
The pin is present and aligns with the mark on the pullley.
I spun the magneto CW.
No evidence of engine failure due to seizure. A ring broke, and it very much looked like it snagged on a sharp edge on the exhaust port.
I’’m going to start it (hopefully) with premix and auxiliary fuel tank. Hopefully I will see the “piston” move and oil squirting up my clear tube to the carb.
Will report back after the weekend!

The engine runs counter-clockwise.
Most oil pumps have a ratcheting mechanism in the drive (some don't).
If you are spinning the engine clockwise AND the pump has a ratcheting wheel, the pump piston will NOT move.

You could try spinning it counter-clockwise and see if your pump piston will move in and out.
If it does, no problem.
If it doesn't, further troubleshooting is required.