Excessive Smoke at Startup II

[Wellcraft238]

My 95 250 2 stroke is smoking like a banchi at start up. I've experimented and left the engine vertical overnight and there is some, but a liveable smoke show the next day when starting. If I store it with engine tilted up, there is lots and lots of smoke. This leads me to believe the oil is draining into the airbox and is sucked in at start up. I have a Mikuni oil pump and removed it to replace the oring on the backside (didn't help, but couldn't get the spacer out to replace that oring). There is no sign of oil on any external part of the pump (even the back). Is there a check valve issue in the pump? if so, can it be fixed?
Thanks!

[rodbolt17]

there is an oil output test.
I use a graduated tube with marks on it and measure consumption.
the check valves are testable and replacable.
if you use the consumption test multiply the output by 6 and that will be the consumption.

[Wellcraft238]

Thanks.

I may mark the reservior after shutting the motor down, and then tilt the engine for most of the day to see how much syphoring is occuring. Can you educate me on the check valve? location (inside pump?) how to access, where to find a replacement?

[Wellcraft238]

Next tests: Tilt engine up and see if oil drains down vent tube. Then investigate to see where oil is leaking in the check valves and maybe clean them now that I know where they are...

[rodbolt17]

there are 6 of them,inline not in the pump.