pullmytrigger

My neighbor (who is in his early 80s) brother passed and he ended up with this boat. Its been sitting for a couple years and he wants to clean it up, get it running and sell it. He calls me because Im the "boat guy" on the street. but Im at a loss here. Anyone know offhand what year this engine is? If we knew what year it was we could at least buy a Clymer manual for it. Looks to me like its very low on oil on the sight glass on the cowl . Where do you put the oil in? lol Should we put a little 2 stroke oil in the cylinders and knock the starter over slowly before trying to fire it?

rak rua

Looks like late 80’s going by the cowl.
Don’t they have a larger remote oil tank in the boat, that feeds to the small reservoir you can see through the sight window? Make sure there’s oil in that small reservoir.

If it were mine, I’d try turning it over, it’s a 2 stroke outboard and built tough. Remove the plugs, connect a battery and touch the key a couple of times first. (Disclaimer…….wait and see if someone agrees with me before jumping in )

If it turns over ok, get some clean fuel, screw the plugs in, or replace, and fire it up in a tank. Watch closely for water from the tee-tale, impeller could be a mess.

RR

speicher lane

If you are in the boat looking att the engine, the front cover plate of the cowl pops out like a door and there are two spring clasps that clam the 2 (left and right) sides of the engine cowl together.... the two stroke reservoir fill cap is just under the cowl.

Alternatively, there was a period where the front plate had a pinch to release on the bottom of the front plate and the front cover pivoted up to remove but that looks like it probable swings open like a door to get to the main cowl clamps. You would feel it on the bottom of the cover if you felt under the cover plate - either way the front cover has to come off to get to the main clasps.

speicher lane

just went down stairs and found and old manual for that era of 3 and 4 cylinder 2 strokes - it has everything but how to remove the cover plate to get to the cowl.....just throwing it out there, some of the smaller mercs had a barb on each side of the back of the cover that went into a rubber grommet on the cowl to secure it in place

The "80hp" 4 cyl. was made 1979(re 1980) -1983 and was a 75 hp there on (newer) according to the book

rak rua

I wouldn’t normally question you SL but this time, I ‘challenge’.

I thought Merc made blue bands until around ‘83, then a short run of brown/gold band, then around ‘86-87 came the silver/red. Also, I don’t think oil injection came out on Mercs until brown band.

I could be wrong tho’ it was many beers and an awful long time ago……..

RR

speicher lane

Oh hell - challenge away - LOL... and yes it was a LONG time ago...

The "service manual".....it's like a chilton - very broad spectrum but at the time I wasn't buying a Merc manual for a torque spec on one OB.
I looked a bit deeper and it states that the 80 was also put later into production '87-89 which makes sense as oil injection was added in 84.

Somebody may correct me but I think a gremlin that era had was the oil injection and fuel line would get brittle from the heat cycles crammed into the cowl up against the crank case - the injection lines would crack and suck out a piston.... something for the OP to look at

rak rua

Probably right about that Gremlin, I’ve heard the early oil injected motors had some issues and many owners have removed the system altogether and mix their own.

To make things more confusing, they went from a 4cyl, down to a 3cyl in latter years.






A bit more searching, I just found a lay person’s guide to identifying engine year…..
Match tne stickers to your engine!




RR

compedgemarine

the big problem with the early oil injection was the driven gear was plastic and would strip thus stopping the oil "injection". you usually found this problem after the engine seized. most just took out the gear and mixed oil to eliminate the risk.

BillK

Surely there must be some type of engine identification / serial number plate somewhere on the engine rather than guessing ?

Markus

It’s a 3 cylinder 80 hp engine.

For only a few years immediately after the 3 cylinder engines came out, Mercury made 70-80-90.

Then, it was simplified to 75-90.

So whatever that service manual says is likely to be correct.