Bill K.....I'll look for one. thought someone might know exactly right off the top of their heads....this is OSO

87, 88 or 89 according to table above.

Isn’t that close enough given that we are now in 2023?

It's good enough for Mercury

https://www.mercruiserparts.com/80-3-cyl

Could that be the original engine for the boat ?
If it is just check the HIN on the transom for boat and engine year .

Oh Im pretty sure it is.....havent seen the old guy around the house in days, hasn't been working on the boat

OK got the cowl open (thanks to you guys) had 3/4 tank of injector oil, found the battery, connected the neg cable, put it on the charger for 20 min, cranked it for 10/15 sec with a set of my muffs (he'd never seen such a thing lol) and it fired up After about 10 sec water peed out of the indicator. 1 min it would idle. FWD/NEU/REV worked fine, Tilt/trim works fine. Thanks to all you guys Rock!!!!

If the engine has been sitting for much time, you might want to dump the injector oil - some of the cheaper oils available can congeal into a blob on the bottom of the tank and obviously the engine will seize from oil starvation up when everything looks good in terms of oil in the tank..... for the sake of removing a few bolts and dumping the reservoir.

It could be fine, but can be bad news

May be good idea to rebuild/clean carbs after setting that long. Don't want to have piston seizure due to fuel starvation??

The guy's son came over and said the boat didnt run at all last summer and only a couple times the summer before so it hasnt sat as long as we thought. As far a dumping the injector oil and cleaning the carbs the boat is for sale and what someone will likely lowball him on price to they can worry about it.

Agree it is a 3 cyl 80hp, late 80s early 90s. I have 1992 75hp which is the same. Oil fill inside case. Get a hot battery and get it going. The carbs love to plug up on these motors and may be a problem. 3 carbs. Nightmare.