sounds like a nice winter project to me 🙂

carb cover you can make from stainless steel mesh from kitcken ware at dollar store or plastic grid from the hobby store
and 2 bolts

Cowl you can buy used … look around on classified ads or eBay

carb job and ignition you can fix read Leroys on MQ,s

http://www.leeroysramblings.com/OMC_9.5.htm

Headgasket easy to chage (doing mine this month)

expect low compression 65-75 (normal on these) get rid of any water A.S.A. P. like NOW !!!!

exhaust booth condition unknown does not mean it is bad … it is just unknown

conclusion: Don’t give up !!