Mercury 85 hp Blue band Compression

[alhntr]

I'm looking for a older decent motor for my 16 foot starcraft type aluminum v hull with power tilt. Hard to find, all the older engines 50-80 hp do not have power tilt, Anyway I just found on craigsllist a boat with a 85 hp mercury blue band which I gather is 1973 to 1977 and has power tilt. Boat trailer/motor 500.00. I just need the motor. If I check cylinder what numbers should I be looking for. 4 cylinder I'm pretty sure. Good motor ? Thanks My boat has no mfg label. It has a 1969 85 chrysler 85 hp on it with no tilt, pain when I fish lakes with no dock. I will part it out.

 

[Faztbullet]

110+psi

 

[alhntr]

Add also says it needs a timing belt, if broke it ma not be possible to turn over to check compression ? Other way to check ?

 

[racerone]

Timing belt has nothing to do with turning it over and doing a compression test on this 2 stroke motor !!----Have a good look at the wiring before handing over the coins.

 

[The Force power]

like what Faztbullet stated; 110 psi or more

However make sure the psi-pressures are within 4-6 psi from each other with dry cylinders!!
When oil or any other lubrication is added to the cylinders just before testing, you can get readings of 120-150 with cracked rings.
older Mercury's wiring is notorious for deteriorating wiring (almost all wires inside the Cowl will need to be replaced/repaired)
be careful when buying

Now that I read everything;

don't go by the wrap to determine on what you're about to buy; go by serial#
post the number and we'll tell you exactly

 

[alhntr]

Thanks guys, another option, Boat shop in Salt lake has a redband merc 50 hp, New lower end , impeller, good compression, 12 month warranty, but I think with 2 people and gear in boat it might e a little under powered, like the 65-75 hp range. But the 85 merc only weighs about 250 dry....40 lbs less than that old Chrysler.

 

[jimmbo]

Myself I would pass on the 4 cylinder 85hp and get an inline 6 90hp, 50% increase in displacement means a lot more low end grunt. Exhaust Tuning on a 6 is much easier than on a 4, and is more effective over a larger rpm range

 

[The Force power]

For your safety;

Find out more info on your boat and it capacities at that point you can make a more educated decision on what motor to strap on it.
whatever motor your buying; the earlier posts apply

Happy hunting

 

[alhntr]

Here is my old aluminum 16 ft fishing boat. No ID tag anywhere. It might be a old chrysler boat who knows. Nice wooded carpeted floor, good room for fishing. Just find me a better motor. Also I am going to replace the wooden transom. It is rotted and bowed. Fun project....oh boy.

 

[Faztbullet]

I would be leary if timig belt was broken as distributer/trigger could be locked up ...serious change$$ if damaged

 

[alhntr]

Is there a method to check that.

 

[alhntr]

Or the distrubuter/trigger lockup caused the belt to break perhaps.

 

[Chris1956]

The PTT on that motor was good for the time, but is likely to be in questionable shape by now. The ign system was good for it's time, but is likely to be questionable by now.

The engine wiring harness will be shot, unless it has been replaced (about $100). Ign components are expensive i.e. Switchbox is $200+, trigger is $220, distributor cap is $150, wires $10ea.

However, I do like the design of the motor. It packs good power into light weight and small footprint. Maybe a 3 cylinder Merc from the 90s instead? It will have newer ign and PTT which will be an improvement.

 

[alhntr]

Thanks all for the input. I also have a line on a 1986 75 hp mercury...300 miles away. The moved from Montana and lost the ingition key.....great. Still on boat, asking 750. Have to find wiring diagram, maybe I can jump the switch if and when I can get there.

 

[alhntr]

Or spend another 1000.00 and get a 90's model. Yikes

 

[racerone]

I believe the 86 model 75 HP is a 4 cylinder and a newer version of the 85 but prop rated.-------I like the way those motors run if in good condition.----" lost the key " could be truthful .----Or it could mean it won't start and there is no way to do the compression test.---Just saying.

 

[Markiecochran]

I have a1994 sea raider f14 90hp sport jet and have found a 1990 85hp force....does anyone know if the crank splines are the same?

 

[racerone]

No 1990 model 85 HP shown-----The Sportjet may have oil injection and the outboard does not.----The part # on 85 / 90 HP Force cranks is different.----See a dealer for exact info.------Contact the " help line " at say Crowly Marine.

 

[Chris1956]

Gee, "lost the key" is easy to fix. Take the cowling off and jumper the starter solenoid to crank the motor and check compression.

To check spark, disconnect the black/yellow wire on the switchbox, and jumper the starter solenoid to crank her. You should get spark on all cylinders.

BTW - there are only about 10 keys for all MerControls. A dealer will have a copy.

$750 for a 1986 motor is quite high. I bought a 1993 Merc V6 for $1K, about 8 years ago. I could likely get one for $200 now....

 

[Tassie 1]

Your looking at motors that are very old, the redband could be 50 yrs old, last blueband was early 80's
Chrysler '84...
they may have had an easy life but could also be 10 mins away from going BOOM

you will probably spend more time fixing them than using them
I know its hard to find money for hobbies at times but it is what it is,

and l have outboards ranging between 1960 to 1979 as well as later models
the older ones always need more "love" and tinkering,
which can be " fun " too