Topic: “BRAND NEW” 1986 Mercury 4 HP ????? – Antique Outboard Motor Club,Inc

This topic has 25 replies, 8 voices, and was last updated 4 years, 3 months ago by fleetwin.

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August 5, 2020 at 5:27 pm #210927
Harmattan1
Participant
Yesterday, I picked up a 1986 Mercury 4 HP outboard. The unique thing about this engine is that it was still sealed in the manufacturers shipping box until a few weeks ago when the persons I bought it from opened the shipping container and did a visual inspection, nothing else. This motor is brand new and has never been started since it left the Merc factory back in 1986. Last night, I took it out of its shipping container and was able to get eyes on the whole motor. The thing is so new, there isnt a scratch, nick, or anything but some dust from being in the shipping box for all those years. I took the upper cowl off and everything under the hood is brand new. The wires, the paint, the plastics, the rubber items, everything is factory new. It is as if Doc from Back to the Future just dropped this thing off after taking a trip 35 years into the past. It looks that good and even better. I have attached 2 pics showing the left and right side pics of the motor on my home made outboard mount.
I contacted Mercury and they seem to think it would be best to change out the original impeller, the seals to the lower unit gear case screws, and some other inner seals. With what I am seeing on the outside of this motor, I am very tempted to just start the motor up and see how good it runs, how good the water circulates through, and all the rest.
I have all the original factory paperwork including the dealer/customer questionaire for feedback to the factory. This thing even came with a separate 3 gal. gas tank AND the rubber fuel line w/connectors and ball hand pump. I mean, everything is there. I almost feel like sending it to the Smithsonian for future posterity………LOL.
Anyway, all this to ask if there would be any recommendations regarding this motor and what I might do to prepare it for first use? Gentleman, it almost feels like the first time with this one…………LOL. Any suggestions would be taken into consideration and processed through upper management for decision making procedural protocol……………… Thanks in advance…

Harmattan 1
August 5, 2020 at 6:21 pm #210936
dave-bernard
Participant
US Member
first of all I would keep it untouched…..
That being said, double up on the oil for the first 2 tanks at least.
follow mercury advice.
that is my opinion.
August 5, 2020 at 7:24 pm #210940
crosbyman
Participant
Canada Member - 2 Years
info… if USA version

http://www.marineengine.com/parts/mercury-outboard-parts/4-1-cyl-product-of-usa/5595532-and-up-usa/flywheel-and-ignition-components

the 3.9-4.5 Mercs till 1985 from Leroy’s …. probably much like yours
http://www.leeroysramblings.com/mercury_4.5.htm

great find !!

Joining AOMCI has priviledges 🙂
August 6, 2020 at 5:32 am #210962
billw
Participant
US Member
If you intend to run it, I would change the impeller, for sure. They take a bad set after just a few years. You could probably do it without scratching anything if you’re careful, because the nuts holding the lower unit on are not painted. Never were.

Long live American manufacturing!
August 6, 2020 at 10:08 am #210978
lindy46
Participant
billw wrote:

If you intend to run it, I would change the impeller, for sure. They take a bad set after just a few years. You could probably do it without scratching anything if you’re careful, because the nuts holding the lower unit on are not painted. Never were.

And I’d put some fresh gearcase oil in it.
August 6, 2020 at 1:50 pm #210990
fleetwin
Participant
US Member - 2 Years
Well, I really don’t think the lower unit seals need to be changed. The engine has never been used, so am guessing the fuel hoses are OK also. Just push/grab the hoses to see if they are flexible….I guess the fuel hoses should be changed if they are stiff and won’t move/wobble easily…
Probably best to change the gear lube, at least check to make sure it is full.
I don’t think you will have any impeller issues caused by just starting the engine, but it is best to replace the impeller in the near future….
August 6, 2020 at 4:57 pm #211017
billw
Participant
US Member
Little Mercs have very small, high pressure/low volume impellers, sort of like a 9.9/15 OMC but smaller and tighter. They take a bad set and have a strong tendency to bend a bade backward. In my experience, anything more than two years old starts to be suspect. So, 35 years…..? What if you did have a failure and toasted that beautiful thing? I know I wouldn’t trust a 35 year old Merc impeller; but your luck may vary….

Long live American manufacturing!
August 6, 2020 at 6:55 pm #211034
fleetwin
Participant
US Member - 2 Years
billw wrote:

Little Mercs have very small, high pressure/low volume impellers, sort of like a 9.9/15 OMC but smaller and tighter. They take a bad set and have a strong tendency to bend a bade backward. In my experience, anything more than two years old starts to be suspect. So, 35 years…..? What if you did have a failure and toasted that beautiful thing? I know I wouldn’t trust a 35 year old Merc impeller; but your luck may vary….

Like Bill says, you don’t want to take a chance on hurting that beautiful new Merc time capsule. This engine is the last of the US Merc built two stroke 4hps, so don’t take any chances…
Replacing the impeller on these engines is pretty easy, no shift linkage to disconnect like most of the OMCs. If you decide to change the impeller, please use the OEM Merc impeller, aftermarket water pump parts can be troublesome sometimes….
August 6, 2020 at 8:37 pm #211043
dave-bernard
Participant
US Member
If you are going to use this motor don’t use the tank and hose. keep it for show. you wont get another. JMHO.
also the same for the prop.
- This reply was modified 4 years, 3 months ago by dave-bernard.
August 12, 2020 at 12:22 am #211380
Harmattan1
Participant
That is a great idea, I will try to find another tank and pressure hose. I would suspect it would be easy to find one for a motor of that vintage. 86 isnt that far behind us, but far enough I suppose. I put some pics to show the original box, tank, and pressure hose. I havent even taken the wire wrapper off the fuel hose that keeps it wrapped as it is.
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