Try putting it in the water at the ramp making sure that the gearcase is fully submerged at least 5" above the gearcase joint. See if it pees. I've seen Yamahas that get finicky with flush attachments and not pump water correctly. My 115 SHO needs to have the flush attachment "just right" for it...
I did some further research and in fact, found that there is no shift connector to disconnect. This engine is splined top and bottom of a one piece shift shaft. It has a 1/2 moon spline top and bottom. If you study the exploded views of the gearcase and midsection you can get a better...
It will come apart, I once spent 14 hours trying to remove two gear cases on a pair of 2003 75hp Mercs from Naples, Florida. They had never been apart in 10 years in salt water. I had to pull both powerheads to get the driveshafts free so with heat and a dead blow hammer ,wiggling, wedges and...
There is salt packed between the bolt and the housing. You will need to heat the housing around the bolt to expand the aluminum to release the salt grip. Use propane or MAPP gas torch to get the job done. Heat in circles around the stuck bolt. Do not directly heat the bolt stub. The goal is to...
I looked at 1941 also, the 41 and 47 were the same engine since WWII put a stop to outboard production for the aluminum needs to support the war effort. I think your engine is missing some parts.