M90A Oil Injection Verification/Removal

[Lazy D]

I purchased a used 1992 M90A motor and have done a fair amount of work to make sure it's in top shape, but I haven't gotten comportable with the oil injection on this older motor.

I replaced a defective oil level sensor, cleaned the oil tank and filter, replaced the lines, primed the pump and made the appropiate adjustment according to the manual. I've been watching the oil level in the tank while running on mixed gas. It's is pumping oil, but I've not been able to determine that it's pumping enough. I run at low rpms and it seems to be significantly less than 50:1.

I looked for a section in the manual to verify the pump is working properly, but only found the adjustment section.

I'm courious about the dependability of the M90A pumps and if I should consider mixing gas and bypassing the oil injection.

If taking the bypass route, what's the best method?

Thanks,
Mark

 

[tohatsu_guru]

The pump system is flawless and no one ever elimanates it. The service manual gives instructions on how to measure the oil flow rate.

 

[Lazy D]

I couldn't locate the instructions to measure the flow rate, just the adjustment.

I did notice that there are two versions of the pump plumbing. One mixes oil into the fuel line, mine injects oil on the intake side of each carb.

Mark