Engine Type/model?

[Toad67]

I have a project boat with an 85hp Mercury, looks identical to this one in pic, but there is a name for the 85 and I can’t remember what it’s called. Are these motors pretty much identical as far as design/performance? My 85 needs work, found this 90hp for sale and it runs. My project boat is a “Stinger” by Wriedt custum boats.
Sorry, I’m not a boat guy.

 

[Scott Danforth]

but there is a name for the 85 and I can’t remember what it’s called. .

Fred???? I like to name them Fred. are you looking for the term "outboard"???? because that is what it is called.

it will have a specific model number.

 

[jimmbo]

I highly doubt it looks Identical. The engine in the picture has a 1979 cowl. It is a six cylinder. The last time there was a 6 cylinder 85hp was in the early 1960s and there were considerable appearance differences between the pre 1965 engines and the post 64 engines. From 1973 thru 1977 there was an 85hp, but it was a 4 cylinder, and would not be as tall as the 90.

 

[racerone]

Then the 85 HP " thunderbolt " would be a 4 cylinder and about a 78 / 79 model.----Posting pictures of the actual motor you have is the best!

 

[Toad67]

Thank you racerone, “Thunderbolt” yes. Outboard, would of never guessed Lol.

 

[Scott Danforth]

Thunderbolt is Mercury Marine's trade mark name for the ignition system developed by Carl Kiekhaefer. sort of like Kleenix is for booger tissue

 

[jimmbo]

Then the 85 HP " thunderbolt " would be a 4 cylinder and about a 78 / 79 model.----Posting pictures of the actual motor you have is the best!

The last year for the 4 cylinder 85 was 77

 

[merc850]

It is a 6 cylinder Merc 90 as these happy boaters will tell you.

 

[jimmbo]

It is a 6 cylinder Merc 90 as these happy boaters will tell you.

He said his motor was Identical to the motor in the pic, which was a 1979 90hp, but that it was an 85hp. To some people, a merc from the early 60s looks the same as one from the 70s and early 80s. Well, they are all painted Phantom Black

 

[merc850]

Yeah well I just wanted to post that hot babe and motor.

 

[jimmbo]

Yeah they did have better brochures in the 60s, 70s, and 80s. later ones always seemed to only show fishermen, Boring

 

[racerone]

He said " looks identical " and I took that to only mean the decals were the same.----I mentioned for the poster to post a PICTURE of his motor so as to not confuse anyone.

 

[jimmbo]

We will see what is revealed if and when a pic is posted. A Serial # would be better, but then I have seen 150hp inline 6s engines on post 1983 transom brackets... Lot of FrankenMercs popping up

 

[Toad67]

I’ve only seen the 90hp in the pic I posted and it’s not local so I can’t go check it out, so my thinking is since it’s a 90hp and mine is an 85hp that it would fit on my boat. What’s the chances it wouldn’t fit? It’s a 10hr drive to get it.
here is the serial # on the 85hp.

 

[GA_Boater]

Post a link to the ad. If it has pics!

 

[Toad67]

Here is the only pic of motor

 

[merc850]

My source says 4092965 thru 4366801 were 1975 4 cyl. models. That looks like it has been re - decaled to a 1979.

 

[jimmbo]

I misread the original Post. Me Bad:embarassed:

Differences between an 85 and a 90

85hp 4 cylinders 66.6 cubic inches WOT range 5000 - 5500 gear ratio 2.3:1
90hp 6 cylinders 99.8 cubic inches WOT range 4500 - 5000 gear ratio 2:1

The 90 has a 50% increase in displacement for only 5 HP. That engine has far greater low end torque than the smaller 85. It will translate into very rapid Hole Shot when propped for about 5000 rpm. Propping for 4800 will yield highest speed. Top speed will be about 1, maybe 2 mph faster than the 85. Propping it for above 5000 will result in a rapid drop in HP as that engine has very small ports. It runs great up to 5000, but develops Asthma above that.

Because of the lower RPM range and the Taller lower unit gears, the prop that worked on one will often be fine on the other

 

[Toad67]

Thanks guys appreciate all the info.

 

[The Force power]

Yeah well I just wanted to post that hot babe and motor.

Hey! that's my mom lol