Working in this. Do you happen to have any pics of rub rail? PO changed it out to something unconventional and Id like to fix that. Plus I have a leak I thing is originating there so I must investigate. Any pics of the Companion way trim as well would be appreciated.Sure. Glad to help.
The 1GM is a good little engine and overall quite reliable. A few pieces of advice specific to this engine:
The raw water pump on these is lousy and goes through seals. You'll know the seals are bad when you see water dripping from the bottom of the pump. What makes this failure especially insidious is that your engine probably has mild steel oil lines, one of which is right below this pump and can rust out as a result of the water dripping on it if you don't deal with the leak right away. (I say "probably" because at some point Yanmar switched to a different material less prone to corrosion for these lines.) You can have the seals replaced by a shop (such as Depco Pump) or learn to replace them yourself. (You'll find some YouTube videos on how to do that.)
Also, inspect the exhaust elbow as part of your seasonal maintenace. It can get plugged up. But another aspect of this design is that there is an inner tube that can rot and develop holes in it, and if that happens it will allow cooling water into the cylinder--no bueno. So pull that elbow periodically and give it a good inspection.