You have the bridged port exhaust and these engines are prone when water pumps get weak the bridge expands and scuffs the exhaust side of piston, You will find when you tear it down piston may have a a small oil hole for bridge. The replacement pistons will not. I drill them in piston to oil...
You have to ground the wht/blk wire from pack to disable QS, just unplugging does nothing. Some packs will go into QS with it bypassed but couple of quick blimps of throttle over 1500rpm will kicker out
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
