Mercury 85 HP year ID

fwo2704

Recruit
Joined
May 18, 2008
Messages
2
Trying to determine year on my 85hp merc outboard. Has thunderbolt ignition and found only one website for ID (which indicates a 1977). Every other web site I go to including looking for parts, my serial number doesn't fall within the range for any year. It's an inline 4 with serial number of 483 3446. Another number found on the side of the engine between the number 2 and 3 cyclinders is 847 3490 and doesn't seem to match up to anything. I am new to outboards and just bought this thing. It's on the back of a 1970 Aquatron Corp 15.10' bowrider (so old it doesn't even list make and model on the title).

So any help with this project would be appreciated. The motor turns over but has zero compression in #1. No idea as to how long it has set. I was told it was running and the old owner (who probably knows less about boats than I do) changed the plugs and wires and it hasn't started since. It does have new plugs but like nothing I have ever seen. Flat across the bottom with a small hole in them. Also the wires are resister type (could this be incompatible with this motor?) Also distributer cap and rotor look worn and corroded and I haven't been able locate either a new cap or rotor for it on any of the web sites. At least not with the serial number range/year that I am told this motor is (1977 motor???). Thanks again for any help.

impaitently waiting for manual to arrive so I can do some serious reading and get started working on this thing and get in the water.
 
Joined
Jun 23, 2008
Messages
7
Re: Mercury 85 HP year ID

its a 1973 for the last time!!!!!!!!! i have the same motor thats the only year it was made !!!!!!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,942
Re: Mercury 85 HP year ID

You can look up the year by serial number on the maxrules.com website. However, it is not a 1977, if it has a distributor.

The plug wires are solid stainless steel cores. They screw into the dissy cap. The rotor is not removeable. The dissy caps cost $100+. New wires may be had at oldmercs.com

#1 cylinder is usually the first to fail due to overheating, lean mixture, improper spark timing, etc. it usually means disassembly, bore the cylinder oversize, install oversize piston and re assemble. It is also very important to fix the cause of the damage in the first place.
 
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