You never opened and changed ( or atleast checked)thermostat. Always go there anytime you replace impellar. Excellent video however. I imagine there’s a ton of corrosion inside the water jackets and you will struggle with overheating issues. And possibly oil leaks in power head and lower unit. These 80’s model hondas last forever if well cared for. I have 2 of the 5hp still in use today
I’ve encountered a few things like bad kill switch, corroded ground, and a spark plug connecter not touching the wire to the CDI for no spark. You could also try a spark test light or ground it to the block to see if it sparks
