Is a 1986 Merc 75HP similar to the old 85HP motors?

[Laker99]

I have the opportunity to buy a 1986 Mercury 75HP similar to the one in the photo. Is this motor similar to the 4 cyl 65HPs from the sixties and the 85HP ones from the seventies? The 1986 motor I am looking at has trim and tilt. The reason that I am asking is that I am planning to put it on a 1969 boat and wanted to decal it to look similar to motors from then. I know it is a 4 cyl, weighs 265 pounds, and the cowling/top hat shape looks similar to me. This was the only midrange HP motor during that year that was a 4 cyl so I thought Mercury may have just taken something they had and put in electronic ignition, the different swivel, and tilt/trim. I also know they went from crank rated to prop rated HP around this time so I thought they may have just taken the old 85HP and called it a 75HP.

I know the last of the 115HP Towers of Power during the mid-eighties had these upgrades. I had a friend tell me that the old Merc 4 cyls were solid engines but the 3 cylinders that replaced them weren't as good of motors. And this option would allow me to have a more modern motor that looks like an older one to 99% of people that would ever see it.

Thanks for the input.

 

[Faztbullet]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

It the same motor as made since 1969, just a few design changes in ignition,carbs and midsection for trim. It is a cousin to the 4 cylinder 65. It is a prop rated motor at 77hp at prop and about 85 at powerhead.

 

[Laker99]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

It the same motor as made since 1969, just a few design changes in ignition,carbs and midsection for trim. It is a cousin to the 4 cylinder 65. It is a prop rated motor at 77hp at prop and about 85 at powerhead.

I would think this would be a pretty solid motor. Is that your opinion too? Thanks for the info. Don

 

[Faztbullet]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

Yep...good motor as long as its up to par in compression.

 

[Chinewalker]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

To answer your other question, yes, you could easily find a face and wrap to dress it up as and old '60s Red Striper.

 

[roscoe]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

Have you gone to look at the motor in the picture? Its priced right, but doesn't have tilt.

I was tempted, but with Christmas, taxes, and insurance all due, I decided not to tempt myself.

 

[Laker99]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

Have you gone to look at the motor in the picture? Its priced right, but doesn't have tilt.

I was tempted, but with Christmas, taxes, and insurance all due, I decided not to tempt myself.

That was just a photo I found. Its not the actual motor I am considering.

 

[Laker99]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

I ran across a 1985 Merc 75HP at our lake that runs but the lower unit has problems. It has title problems coming out of an estate but I think I can figure that out without much trouble. The seller only wants $150 for it. I'm wondering if I should buy it based on how much trouble and expense getting the lower unit straightened out would be. I wonder how much having the lower unit rebuilt would cost or buying a replacement. I think this level of mechanics is beyond my ability. I do have a guy that is a retired certified Merc mechanic that will work on it for $55 an hour. Also, would lower units from the old 65s and 85s work on this model? This seems like a nice motor with controls and tilt and trim. The guy said we can start it up (without the lower unit on there) but that doesn't sound advisable to me. I realize it wouldn't have cooling water but it also seems like it might be hard on the powerhead. But it would be nice to run it a little bit and check the compression. I'm sure this would be a great deal for someone that knows what they are doing but might not be a good option for me. I'm also not interested in buying it and parting it out.

 

[racerone]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

No problem starting it up with no lower unit.---Just do not run it for more than 10 seconds with out letting it cool down.

 

[Laker99]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

What's your opinion on how much of a project/expense it will be to rebuild the lower unit or find a replacement?

 

[racerone]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

That all depends on your location as to what is available used.----Cost to rebuild can be astronomical if major parts are needed.--Shafts and gears are very pricey.

 

[emckelvy]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

IMHO, I'd look for parts on your local Craigslist, in the Boats section. It's very likely you'll find a dead parts motor with good lower unit for cheap.

Far as the motor itself, for the price of $150, that's a pretty safe purchase. The power trim 'n tilt assembly alone is worth a lot more than that on eBay.

You can run it safely without the lower unit, just adapt a hose to the copper water supply tube, and connect a water supply. Give it enough pressure to develop a good telltale, and have at it.

Just be really careful with application of throttle; with minimal exhaust restriction and Zero drag on the crankshaft, she's gonna want to rev up quickly! You should be able to get a good idea of how it sounds mechanically, whether it's idling well, etc.

HTH & let us know what happens.........ed

 

[Laker99]

Re: Is a 1986 Merc 75HP similar to the old 85HP motors?

I'm going to check it out on Friday when I am at the lake and if it is still available. Thanks for the info.