I would start by dropping the LU and checking the water pump and replacing the impeller. If the housing is in bad shape replace it too. Especially since you just got the motor and it's history is probably unknown.
Those are the correct part numbers.....not sure why they don't fit your motor. Might give Franz Marine a call in the morning. Tell him what you got and he should have a solution.
It has been said that the best kind of oil is CLEAN oil.......of the proper viscosity. Synthetics really shine for temperature extremes and severe duty use.
No problem.....that thread is probably the most important one on this forum. My manual has the same info, but that thread seems to be easier to follow.
https://forums.iboats.com/threads/if-you-have-high-charge-voltage-please-read.249235/post-1734334 Here is the link to the one about high charge voltage......it may be the last one that is missing.
Maybe a year ago? I sent GA_Boater a PM with some of these missing links on this forum......he had them working then after a short time they reverted back. FYI
https://forums.iboats.com/threads/synchronizing-carbs-and-timing-on-a-75-150-chrysler-or-early-force.420505/ Here is the link jerry......I think it has been missing for a while, had to search for it a while back IIRC....
Once I had rendered the valves unusable, put them in a vise and used vice grips to try to take them apart.......never did get the caps off.....literally broke in half, totally destroyed! Lol. :ROFLMAO:
I started out real careful, went down hill from there.....lol. Got a 10 pack of those o-rings, more than I will ever use, and it only takes 2 for the repair. If ANYBODY needs a couple, let me know. (y)
Its in the stickie by pnwboat....he used Briggs Stratton kit #398188. I have some that I didn't use....ended up buying a rebuilt pump. PM me if you need some.