85hp Merc?

[cesandroid]

Good day, ive been a johnson guy but i saw a merc 85hp for 500 bucks. had a video of it in a tank idling strong. Other than that it was a project boat he threw away due to rot. he wants the motor out of his garage. no controls for it, no working tilt but has the cylinders he says. Is this a big gamble to consider. Are these motors any good?
Thanks

 

[Chris1956]

Gee, what year? Merc 85HP motors were made in the 70's with 4 cylinders. They made 80HP motors later on in the 70's and perhaps some newer models as well. Is it one of those oldies from the 70's? If pre-1976, it may have a distributor. The ign system was sound, but parts are expensive, and a bit hard to get.

In any case, if it is older, say early 2000's or older, most shops will not work on them. At that point, either you fix/maintain it yourself, or it is an nice black anchor.

if it is from the 70's, the engine wiring (if not replaced) is likely bad. The engine harness is easily replaced ($150 or so), but the distributor wires also rot out, and the distributor casing would need replacement ($250 or so).

If it were me, I would not buy a motor with a distributor-based single coil ign system. If it has the more modern ADI system (multiple coils), I would consider it, if the compression in all cylinders was within 15%, and I was pretty sure the gearcase was good. I would be prepared to maintain it myself.

Controls will be at least $150, plus cables and likely some way to graft the wiring will be needed, as the wiring has changed several times between the early 70's and 2000.

 

[racerone]

How can you tell by a video that it is idling strong ?----Was it in gear or neutral?-----Get it cheap and be prepared to spend some time and beer tokens on it.----As stated most shops today work on boats that guarantee them a profit.----Owners of older motors can be reluctant to open the wallet to pay $125 / hr shop time.-----And remember that the techs today are vague on working on these.

 

[Scott Danforth]

Are these motors any good?

40-50 years ago, when the motor was new and maintained, it was a good motor

However 40-50 years later, with unknown maintenance and operation, who knows

As posted above, get it cheap enough. Plan on putting time and money into it

 

[cyclops222]

It is a con man making money.

 

[cesandroid]

Perfect everyone thanks!

 

[Texasmark]

Gee, what year? Merc 85HP motors were made in the 70's with 4 cylinders. They made 80HP motors later on in the 70's and perhaps some newer models as well. Is it one of those oldies from the 70's? If pre-1976, it may have a distributor. The ign system was sound, but parts are expensive, and a bit hard to get.

In any case, if it is older, say early 2000's or older, most shops will not work on them. At that point, either you fix/maintain it yourself, or it is an nice black anchor.

if it is from the 70's, the engine wiring (if not replaced) is likely bad. The engine harness is easily replaced ($150 or so), but the distributor wires also rot out, and the distributor casing would need replacement ($250 or so).

If it were me, I would not buy a motor with a distributor-based single coil ign system. If it has the more modern ADI system (multiple coils), I would consider it, if the compression in all cylinders was within 15%, and I was pretty sure the gearcase was good. I would be prepared to maintain it myself.

Controls will be at least $150, plus cables and likely some way to graft the wiring will be needed, as the wiring has changed several times between the early 70's and 2000.

I bought about a 1974 85 4 cylinder with PTT new. One of the finest engines I ever owned. One thing that stands out is in the winter I would pull up to the ramp, dip my trailer "properly" start the engine...immediate thing, and back off and secure, put my truck/trailer in the parking lot and be on my way while there were usually a number of (varied) folks fiddling with their engines trying to get them started.

I was fishing a large lake where the wind blew more than it didn't and I opted for a larger boat and sold the rig. Controls can be bought on ebay if not available here.

 

[cesandroid]

Good info. The Merc was in a tank in neutral. I cant get the video to post. The pictures of it is all i have including a still picture of the video.

 

[racerone]

Decal were used in 76 /77 model years.

 

[Chris1956]

That motor will have ADI ignition, which is good. As Texasmark says, it was a fine engine, but let me add that it was a fine engine in 1976/7. That was nearly 50 years ago. Is it still fine?

Those motors had a history of the inner exhaust cover and exhaust baffle rotting out, and the wiring losing its insulation. New wiring is likely available, or could be cobbled together fairly simply. Replacement of the exhaust cover or baffle is a different story. Those parts were hard to get in the late 90's. Crowleymarine shows them to be N/A.

 

[redneck joe]

If compression is good, most everything else can be handled.

 

[Chris1956]

Joe, if you added gearcase and late-90's engine or newer to your statement, I would agree with you. However, if the exhaust baffle or exhaust covers have rotted out, even if the compression is good, you will be looking for used engine block parts that are still good, after nearly 50 years. there probably are some of those around, but I would think they will be hard to find.

Also, the 5/16" bolts that hold the exhaust baffle and exhaust covers to the block were originally installed with epoxy. Add the epoxy to the years of corrosion, and you have a recipe for lots of broken bolts.

 

[redneck joe]

Im not into the subtleties of different parts correlating to year classes but I love my 82 50hp and hoping to love my 87 70hp

 

[1960 Starflite]

I acquired a 1975, 850. Very low hours, used just two weeks a year pushing a 22 ft pontoon by original owner. As said the wiring was trash (Mercury must have contracted with an cheap company). I replaced wiring, installed it on my Toon. Once warmed up it starts easily. It does love fuel. I sure wish it had PTT.

 

[racerone]

Find a used trim / tilt unit.-----You can save a lot of fuel by running at 3500 / 3800 RPM on a 2 stroke.

 

[redneck joe]

Find a used trim / tilt unit.-----You can save a lot of fuel by running at 3500 / 3800 RPM on a 2 stroke.

That's about where I run.

 

[racerone]

The 2 strokes when maintained use a bit more fuel.----But they do not get sticker shock on repairs / maintenance at $125/hr or more shops.----Locally I see a lot of fairly new 4 strokes for sale.----Must be a reason.

 

[Nordin]

Nice engines those 4 cylinders 500, 650 and 800/850, early and mid 70es. Later 80Hp and in the mid 80es 75Hp.
I have one 500 1970, one 800 1971 and a 800 1972.
Love those BUT when I look at the web site such as Crowley Marine, Iboat etc and check with the shops in Sweden where I am, I see that the bearing carrier and the nut in the LU for them are N/A.
If you have to work with the LU those two parts are almost stuck and impossible to remove.
You have to drill and crack them to get them loose.

 

[cyclops222]

I took a Sawsall to those bearing shells. 2 or 3 cuts at about 180 or 120 degrees each outer race housing.

 

[Nordin]

Yes there are different ways to remove those parts, saw or drill and crack are some action to get them out.
But the bad thing is that it can be problem to get a new carrier and nut if you have to take the LU apart.
If you find them they can be pretty expensive, the carrier is a whole assembly with needle bearings and seals.