Best 60-90 hp motors of the 70’s-80’s?

[shoestringmariner]

I hope this question is not out of place here. Wondering what makes and models stand out above the rest in terms of longevity, reliability and parts availability? My budget likely dictates a motor from this era.

[bill-loveland]

My vote’s for the Evinrude/Johnson three cylinder 70/75 hp motors, especially if they come with T/T

[dan-in-tn]

My vote would also be either 3 cylinder ( prefer 70hp because of low end ) or V-4 85hp. In particular 1978. 1978 & later you have the later style TNT unit that was so reliable. The 3cylinder 75 can have the long exhaust tuner put in to improve low end so that is not a major problem, but something to be done. Stay away from salt motors of course for this age.
The 1978 85 is the last 92 cu. in. (3 3/8") bore motor. It never had high ring pistons so no problems there. Getting harder to find replacement pistons, but they are out there. They aren’t as bad on fuel if you don’t try to turn them a bunch of RPM. They were a tractor motor. 5000 WOT is about it.
I’m sure the Merc guys have their favorites, but I’m an OMC guy.

Dan in TN

[frankr]

The 85 that Dan said.

[chris-p]

Being very specific I love the 1979 Johnson Stinger.

[fleetwin]

quote Dan in TN:

My vote would also be either 3 cylinder ( prefer 70hp because of low end ) or V-4 85hp. In particular 1978. 1978 & later you have the later style TNT unit that was so reliable. The 3cylinder 75 can have the long exhaust tuner put in to improve low end so that is not a major problem, but something to be done. Stay away from salt motors of course for this age.
The 1978 85 is the last 92 cu. in. (3 3/8") bore motor. It never had high ring pistons so no problems there. Getting harder to find replacement pistons, but they are out there. They aren’t as bad on fuel if you don’t try to turn them a bunch of RPM. They were a tractor motor. 5000 WOT is about it.
I’m sure the Merc guys have their favorites, but I’m an OMC guy.

Dan in TN

I’m with you Dan…Simple, reliable, and easy engines to troubleshoot/repair…

[frankr]

Anybody for Yamaha? Oops, sorry. I’m an OMC guy too. But Yamaha survived when OMC didn’t.

[20mercman]

I would vote for the Mercury inline 6 cylinder 90hp. These were the smallest horsepower of this displacement. These ran smooth, great fuel economy, great low end torque, all around a great motor. We have a 1981 version of this motor since it was brand new, and I could not be more pleased with everything about it.

Steve

Edit: I also like inline 4 cylinder Mercury’s of that vintage, with a caveat. The Mercury 4 cylinder 650 that ended in the early 70’s, were very good motors. I have a 1971 80hp. inline 4 that is also a very nice motor, but can’t hold a candle to the 6 cylinder 90. These ran and idled so well that folks trolled with them in our area. Salmon fishing on Lake Michigan was in it’s heyday then, so a lot of this size motors were sold. The problem with the 80 and 85 hp inline 4’s was that they used the same water pump as the inline 6 cylinder. These cooled almost too much at low speeds and they could wear out or round. I did have my bored out +.030 and it is back to it’s as built performance.

[outbdnut2]

Dad bought a V4 60 HP new in 1965 for his 1958 14′ Aluminum Crestliner Voyager14 (rated somehow for 60 HP) – we skied with it, beat on it, ran trim pin up so it regularly over-revved, cavitating on WOT corners, ran 200+ gallons of gas per summer through it from 1965 to 1984, then traded it on a used I/O. That motor was bulletproof – only replaced impeller, fuel pump diaphragm, and spark plugs. Only downside was it was a bit heavy for that light boat, so handling was somewhat dicey – couldn’t let just anyone drive it. We mixed gas/oil at 40 to 1 using cheap SAE 30 non-detergent oil. I learned to ski barefoot behind that rig.
Dave

[dan-in-tn]

20mercman that is the other motor I was thinking of. Since I am not a Merc guy I didn’t bring it up. It was a totally misunderstood motor. Mercs were alway known for high RPM! This motor came out with low ports & needed to top out at 5000 RPM like the OMC 85. Guys here in TN (bass boaters) just never could except either engine because they wouldn’t scream.
They were both good realiable motors you could count on for a GREAT day of fishing or boating. I thought that’s what it was all about. Other models were built for racing.

Dan in TN

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