Autolube leaks through engine

[Emilenka]

Hi everyone! Im new at this forum but my problem is old. I have a 70b, probably 1989. When i havent started the motor for a couple of days i get heavy smoke when i start. The problem is that the lower cylinder has a whole lot of two stroke oil in it. The autolube seems to leak oil into the engine while its not running. Where do i start to search for faults? Is it time to change the oil pump?
Best regards
Emil

[99yam40]

Leaking check valves would be where I would start if that old of a motor had them

[rodbolt17]

the kien pumps prior to 1990 had the check valves in the pump.
the kien pump has been NLA since 1990.

the later mikuni pumps used inline check valves.