You will likely have to swap driveshaft as its fine spline. Most of the 60-70hp 3 cylinder where 4 spline. If you swap shafts you will need to reshim pinion
If it chit the pinion for no reason (I dont really see the water evidence) the gearcase may be warped. There is a gearcase alignment tool to check this. I will not rebuild a gearcase unless it is checked. I have discarded cases that look almost new that was warped. If not it will chit the gear...
To the original poster.....I charge $95 per carb plus parts. This is removal/install/sonic clean/sync and link. Fuel pump is $95 plus parts. Part would be 4 carb kits @$15.85x4, 4 inlet needles @$11.50 and pump @$31.49 and $16.00 for shop supplies such as fuel ties/carb spray
Someone cut that or came from factory like that. Sleeves are installed/straightened and block is drilled in middle of transfer port webbing. It is only drilled deep enough to dimple the sleeve and a set screw is installed and epoxied over
If you are a DIY working on your personal engine , buy a DVA adapter and a brand name meter. If your going to work on customers buy a analog DVA in link below. Same meter Mercury sales/uses. FLUKE does not sale a meter with built in DVA adapter...