Nissan (Tohatsu) makes a VERY dependable outboard. I have a Nissan 90 on my 1976 AS 170. Clean running economical engine with great performance. Pushes my boat at atround 40 mph trimmed up. You will find tons of them on the commercial mullet boats operating out of Cortez (Bradenton, FL). Met a crab fisherman who has 4900 (yes forty nine HUNDRED) hours on a 90 hp TLDI on a Carolina Skiff. Don's Marine in Bradenton 941-778-5871 can give you a realistic value.
Mickey W
1976 170
Nissan 90 HP