Logo
FULL SITE MENU

find my year make model

P

Portis Left

Contributing Member
i need to try to get you guys to help me find this info on my motor. im sure this is a "here we go again" topic but i think this may be special case.
the only number on this is not on the motor itself but on the part that mounts the motor to the boat. (transom bracket?)
if im in the driver seat and turn around to look...just under the motor i can see a tiny little silver plate on the tilt bracket labeled....

SN: 4603143 (maybe just the transom bracket #?)

ive looked..cant find it.. i called mercury...they cant find it. i talked to some old pros...they cant find it.
ill be happy to look ANYWHERE on this motor people suggest. but know this...its not on any freeze plug i can see.

please bear with me here. worst case scenario ill even resort to posting pictures and letting anyone who will just take random shots at it from looks alone.
nobody around me (shops) wants to work on a motor this old. so i amgoing to have to do it myself. i cant even buy parts.

thanks guys....please hang in there with me. i need this.
P.S. it does say 90 hp on the mid section seen if standing behind the boat.
 
Yes, a picture would help nail down a "range".

If you can't post a pic perhaps a better description.

eg - how many cylinders, colour of the stripes on the cowl (hood).

Any casting numbers you can find on the carbs etc.

Merc did "model runs" so as an example from 1986 thru the summer of 1994 all 6, 8 and 9.9 horse models were mechanically identical so from a parts perspective it's doesn't matter if you have a 1986 or 1993 - all parts will fit either.

So unless your jurisdiction requires an exact year for registration, simply knowing the "range" will be enough to service it and source parts.
 
6 cylinder...the cowl stickers pattern is like snow when a tv channel goes off the air and its tint is blue.....90 horse power written on the leg.....wmk carbs.....3 carbs. the front plate says thunderbolt ignition.
sorry guys. i have the best pictures ready to go. but this website wont let me upload. it tells me somethings wrong with them but not "what" is wrong with them.
 
Well, now we have a few clues.

Merc produced the 90 horse in 1965 then not again until 1978. So it's NOT a 1966 thru 1977 model if it's a 90 :)

Next, I believe you are describing a "blue band" model (with the Thunderbolt Ignition plate on the front of the cowl). Your "blue" might be faded and weather checked but sounds "probable".

They (Merc) used that band colour with the (Thunderbolt plate) between 1980 thru 1983. There was an earlier blue band (1974-77 but those models had a distributor ignition and the 90 wasn't a model during that time).

The WMK carbs were also used in that time range. If you look really close they may be stamped with a number as well (eg. WMK-38).

So from what you have been able to find - assuming you don't have a distributor under the hood (if someone swapped a powerhead and it's not really a 90), it "should be" a 1980/81/82 or 1983 model. After that they changed the band colour (to brown for two years) and then they started building the 90 horse on a 3 cylinder platform a few years later.
 
that is superb. a lot of info at once that has been a sort of mystery to me. so having said that.......mine has plug wires that runs to a cap with a rotor inside. i am embarassed to say it but i can do anything car engine wise (old ones) but this boat motor has me upside down. and depending on what year "you think" it is,
where would be my best chance to fnd a real serial number on this thing? i wish i could post pics. the site just wont let me. if its an 80 then people around here will work on it. but there is nobody around here that will work on older...
 
If it has a distributor then you may have a 78/79 model.

Those had a blue band with a red stripe - but it is possible that the (hood) was changed over the years by a previous owner or the red stripe is so faded out that you can't tell it was there.

I don't know what error 2308 is, but whenever I get a picture error it's usually because it's "too big" for the limits of this server (set by the admin).
 
Portis Left said:
SN: 4603143 (maybe just the transom bracket #?)
Click to expand...
How clear is that serial number to read?

As for a parts guides, with serial number 4603143, the closes you are going to get for a 90 HP 6 cylinder that uses 3 carbs is parts catalog serial number range 4845301 - 5299505 (USA) as it is really close and if your numbers happen to be off some or hard to read, etc., then it's even a better change this is the one you need.
http://www.marineengine.com/parts/mercury-outboard-parts/900-90/4845301-thru-5299505-usa
http://www.mercruiserparts.com/900-90-4845301-thru-5299505

Here's the 90 HP years to parts guide ratio for you,
900 (90.0) 1755444 - 1965.. This would be why 1965 was mentioned above.
900 (90.0) 4845301 - 1978 What I think you may have.

If the serial number really starts out with 460, then all the other engine models that are in and right around the serial number range that uses a 460**** number is considered to be a 1976 - 77 model year.

Some examples for you,
110 4304785 - 4605111 1976
1150 (115.0) 4567952 - 4855152 1977
850 (85.0) 4590512 - 1977
75 4314385 - 4691221 1976

As for posting photos, sometimes I have luck with copying the photo from somewhere else and pasting it here. You may have to use the insert image tool just to the right of Bold, underline Font, size, etc. etc.
 
Last edited:
Portis Left said:
Somebody tell me they can do something with that serial number
Click to expand...
As for serial number compared to the charts available online there isn't/doesn't seem to be any 90 HP's engines with a serial number range that starts with 460.....Only 484 on up which makes it an unusual case. Being the close year found is 1978 for the 484 and the other engine horsepower's that are read as 900 for (90.0), 850 for (85.0), etc. etc. that all have or start with a 460 number is right around 1976 - 77, chances are you have an early release engine model to/for 1978....But it's only a guesstimate and again since that appears to be the case, the info posted in post 10 should help you out with this one... http://www.autorepairmanuals.biz/page/609774

Thanks for posting the serial number photo to help ensure it's clear...Often the number starts of incorrectly due to fat fingering the number during the initial post only to be corrected after having/asking the poster to re-verify the numbers. Hope this helps you out some at least, good luck.
 
Or it's also very possible that sometime in this outboards lifetime something "major" was replaced.

Maybe it's just the "cowl" that got busted and one from a 90 horse was found to replace it etc.
 
Back
Top