Best 60-85 hp motors of the 70-‘s and 80’s?

[shoestringmariner]

Hey guys, my username says it all again…looking for suggestions on the best 60-85 hp motors of the 70’s or 80’s to replace my ‘75 Merc 650.

I can’t afford a new 60 hp Etec or 4 stroke anytime soon, so I’ve got my eyes peeled for motors or boat packages with motors that you all feel are rock solid performers and or good rebuild candidates.

My 650 was running well last year, but after $550 in bills and a used lower unit, I feel I should move it along while I can. Wiring as you merc guys know is questionable and looks rough. I was told the trigger on this was good “for now”

[chinewalker]

3-cylinder OMC, ‘79 & up. I’ve got a 1980 Johnson Stinger 75 – fantastic motor!

[bobw]

I’ll second chinewalker’s comment. Had a 1984 Johnson 75. Loved it but went to a bigger motor – sold the 75hp and it’s still running today with the new owner.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[20mercman]

It always seemed to me that the three cylinder OMC was one of their best mid-range motors. I always thought that the V-4’s shook like a wet dog by comparison. I have a soft spot for the inline 4 cylinder Mercury’s but you can have issues with them with out of round cylinders if they have been trolled a lot. They had the same water pump as the inline 6 and folks would troll with them. They ran too cold and would wear they cylinders out of round. Look for rough idle or stalling as a symptom of out of round. Other wise, I love mine. By the time they are this old, there are going to be issues. Wires loosing their insulation are often an issue. How was it stored, was it taken care of. A lot of mid range motors are in deplorable condition as they often sat outside under the shade tree for the last 20 years. A 20hp or 9.5 often made it to the garage or basement where life was better.

Steve

[shoestringmariner]

Thanks guys. I’ve found an 84, non running with a damaged prop and sheared off skeg. I can weld on a new one and replace the seals, but I know nothing about the powerhead other than it “spins freely”.

Still waiting to hear if it’s power tilt. I can’t tell by photos, or at least my untrained eye can’t.

So basically I’ve approached the owner offering to buy it for parts but I’m nervous to pay too much in case the powerhead is junk too. Is it possible to do compression tests on these motors by rope pull starts? It’s still on the boat but the harness and wiring are all disconnected.

Thoughts?

[fleetwin]

An 84 what?? I am assuming you are talking about an 84 OMC three cylinder engine. This engine sounds like it might be nothing more than parts. A gearcase with the skeg damaged/broken could mean there is damage inside also. You might want to check the gear lube and make sure the prop shaft is not bent. Don’t bother trying to test compression by pulling it over with a rope. Can you hot wire the starter to get more accurate compression readings? Is this a fresh or salt water engine? Does the engine have power trim and tilt?
There are so many factors to consider, it is hard to give any concrete advice. One thing is for sure, you need to accept the fact that buying this engine might end up to buying some parts. So, your offer needs to reflect this gamble….Don

[chris-p]

My vote is for the 75HP Stinger as well! Awesome motors if you can find them! My favourite being the 1979, just for cosmetic reasons.

[chris-p]

Also,…..if you ever need me to have a look at a motor for you, just let me know.

[chinewalker]

Yes, you can rope one over to check compression. You can jump directly to the post on the starter motor and bypass the wiring harness. 120+ psi and even across all three holes.

Power trim model will have wires eminating from the port side clamp bracket, aft of the tilt tube.

• This reply was modified 5 years ago by chinewalker.

[Mumbles]

If you are going to rope it over, remove all of the spark plugs to make it easier to pull and ground their leads. This will prevent damaging any electrical components and also prevent it from starting if the harness is undone.

If you need parts, I have gearcases, pumps, TNT etc. on the Canadian West Coast.

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