Most likely a 85HP Perkins is the good old, reliable Perkins 4.236, that is 4 cylinder, 236 cubic inches displacement
. Horsepower varied depending on application, with commercial
vessel engines de-rated to 75HP. Most pleasure craft 4.236's are rated 85HP.
This is a very durable engine with easy parts
availability almost anywhere. I have a Perkins 4.236 in my Cal 46
with 3,600 hours and no problems. With proper care, you may easily achieve 10,000 hours. The previous owner of my boat had recently completed a circumnavigation
. Due to his severe health
issues, he motored a lot, launch was 11/1967 and I purchased her in March 1982. The engine had 11,000 hours, ran well but consumed a quart of oil
each 24 hours. I bought a new 4.236 in 1987, which I still have.
A complete rebuild
kit is about $1,500, labor cost will vary depending on your location. I rebuild
Perkins engines, mostly 4.108 & 4.154 as they are the most common. A 4.108 Long Block is $4,995, plus a core
engine or +$500. I have not rebuilt a 4.236 as they are the best of the lot and not as common in boats. The #1 application was agricultural, then as power for refrigeration
for railroad cars.
PM if I can help.