Bob, I thought about your idea, but I don’t see how the centrifugal gear force
could move this driveshaft “up” while running.
The drive gear is keyed on the driveshaft, then a trunion like affair slides over
the end of the driveshaft, and is fixed upon the prop shaft.
I’m not sure if the driveshaft can be shimmed higher inside of the trunion or not.
The only shims I see mentioned in the parts diagram is for the prop shaft end play / gear mesh.
I did find mentioned in the 1942 Evinrude repair manual, a paragraph on the two stage
style metal water pump impellers, stating that the “Deflector” should have 1/32″ clearance
on each side. I presume the “deflector” is the plate that separates the upper and lower impeller.
I gather from what the paragraph is saying, that this clearance is in regards to when the upper
and lower impellers are being pressed together, not any “setup” after the fact.
Prepare to be boarded!