Mercury 850 help.. year etc..

[Melaney]

Hey guys, im a new member and have been trolling through these forums a few days now trying to find info on my motor. Its a Mercury 850. Has 90HP on it that has been painted over (although i thought they were 85HP??) Blue stickers. Thunderbolt ignition.. only markings i could find. I know its a 70's but need to know more for parts..

The serial # i found is on a mercury sticker and reads A7152687. i cannot find this number anywhere in my searches. Any help appreciated...

I know i need to swap the impeller (where to source? what other models fit?) but the motor randomly has a habbit of bogging down when going from slow to flat chat.. only does it for half a second, other than that its fine.

And lastly, it does not like reverse at all.... grinds when trying at low revs but will engage at high rpm.. which i only did once for obvious reasons.. is it as easy as dis-assemling and replacing the reverse gear? and where could i locate one of these?


I am fairly nifty with a spanner and this is not my first motor, but my first old motor and im having trouble sourcing the parts i need..


Any help greatly appreciated guys

 

[Melaney]

Re: Mercury 850 help.. year etc..

forgot to add it has electronic tilt and hydro steering too if thats anything?!?!

 

[Gibbles]

Re: Mercury 850 help.. year etc..

How many cylinders?

and get some pictures

 

[Chris1956]

Re: Mercury 850 help.. year etc..

In the 70s and 80s, 85HP motors were inline 4 cylinders. The 90HP motors were inline sixes. In the 60s and 90s those rules do not hold true. If that A number is a serial number, you can look up the year at the maxrules.com website. Likely early 90s.

How many cylinders?

 

[Melaney]

Re: Mercury 850 help.. year etc..

Sorry, its is an inline 4.. i have looked through the maxrules site and it is not there..

will take pics asap

 

[Melaney]

Re: Mercury 850 help.. year etc..

and its 2 stroke (premixed)

 

[oldman570]

Re: Mercury 850 help.. year etc..

Welcome to IBoats. I run a check on the info you have given, and it looks to be a 80 hp motor made between 1984 and1986 as far as I can tell. After 1986 Mercury motors that size were 3 cylender motors. Sometimes the water pump impeller will have a part # on one side near the center brass that you can go buy. As for the reverse problem, I would check the linkage first to see if it is out of adjustment before getting into the gear housing. Parts can be bought at IBoats and would be best if you call and talk to them as to ordering correct parts for your motor. Marine Engines.com and Old Mercs.com are other sites that might also be helpful.
Hope this helps, and boat safely.

 

[Melaney]

Re: Mercury 850 help.. year etc..

thank you so much. i didnt think of checking linkages.. and ill pull the impeller out and have a look, maybe even just try and match it up.

kind of nice to know the motor could be 10 years newer than i thought

 

[carholme]

Re: Mercury 850 help.. year etc..

Melaney;

Something seems goofy with that s/n with 7 numbers and a letter in front of it. Can you verify the s/n or post a picture of it?

How did you determine that it is a model 850?

Where is the 90hp painted over?

What do you mean by a Mercury sticker, is it metal (located between the transom clamps) or the peel and stick type (usually found on the gear leg)?


The last Canadian built 85hp., 4 cylinder was in 1977 and the starting s/n for that year was 7091098.

85 1977 4 4590512 7091098

Is this the colouring of your decals?

http://www.nymarine.ca/77ME850WEBPIC.gif

Gerry

 

[Melaney]

Re: Mercury 850 help.. year etc..

Seems i have made a fool of myself, there is no 850 markings on the motor... it has been in my head as i thought it may have been while going through my researches..... pics:

http://imageshack.us/photo/my-images/141/img1193ts.jpg/
http://imageshack.us/photo/my-images/194/img1195s.jpg/
http://imageshack.us/photo/my-images/710/img1197xe.jpg/
http://imageshack.us/photo/my-images/847/img1198nz.jpg/
where the 90 has been painted over
http://imageshack.us/photo/my-images/220/img1199s.jpg/
http://imageshack.us/photo/my-images/534/img1200py.jpg/
http://imageshack.us/photo/my-images/851/img1201gc.jpg/
http://imageshack.us/photo/my-images/685/img1202re.jpg/
http://imageshack.us/photo/my-images/189/img1203r.jpg/

 

[carholme]

Re: Mercury 850 help.. year etc..

Melaney;

At least the picture of the s/n shows that it is A715268, not s/n
A7152687 as in the first post.

However A715268 comes up as a model:

1090726 MERCURY 1986 90,

which is a six cylinder inline.

Can you get a closer picture of the tag shown in this picture?

http://imageshack.us/photo/my-images/194/img1195s.jpg/

As well, to verify the s/n, do you see a disc like this anywhere on the powerhead?

http://img84.imageshack.us/img84/8224/391496208.jpg

Gerry

 

[Chris1956]

Re: Mercury 850 help.. year etc..

Very interesting. The Wrap cowling decal is from a 1977/78 Merc. Since it is 4 cylinder, it is likely an 850, if the block is from that vintage. The quick disconnect plug is the same late 70s vintage. The transom bracket is newer, maybe late 80s.

 

[Melaney]

Re: Mercury 850 help.. year etc..

carholme: there is actually a 7 on the end of the serial number. i will take closer pics of any other markings i can find...

This is all getting too confusing haha

 

[gwukena]

Re: Mercury 850 help.. year etc..

It's going to get a lot more confusing yet.
You've got a Frankenmerc. The transom clamp/power trim is definetlly from a mid 80's unit. The powerhead electrical cobra connector is mid to late 70's. Cowl wrap is mid 70's. You need to find a s/n on the power head, like carholme said, look for a welch plug on the powerhead with the s/n stamped on it. Also look around crankcase parting lines for s/n of powerhead. Get s/n off powerhead and you can figure out the hp and year. Did you just get this unit? If so ask previous owner of any repairs. Can pretty well guarantee that's not the original paint. The lower unit looks like it's off a late 70's/80's unit. I would check your gear ratio. Count how many turns of flywheel to turn prop one turn. I believe inline 4's and 6's were different. Have you run the unit?, How was rpm and speed? What pitch of prop?

Hth

Gary

 

[oldman570]

Re: Mercury 850 help.. year etc..

qwukena and carholme are right on the mark. It is a Frankenmerc motor that has had the trasom bracket changed out, probbly for the tilt an trim. Check the fresse plug on the block witch should be the serial number. Best bet for the pump impeller is to take it out and check for a part number on it as there were more that was made. Serria still has the impeller for them and can cross ref for the one you need. You can call Iboats and i am sure that they will be able to get what you need for parts. The reverse gear can still be bought, if not at Iboats, at Marine Engines.com
Have FUN and be SAFE

 

[Melaney]

Re: (c) pozycjonowanie

Re: (c) pozycjonowanie

Haha, Frankenmerc.. i like it... ive only had it a few months but have been out in it heaps.. it doesnt have a taco but cruises on 30ish knots no worries... i have noticed it is alot quieter than my 150HP V6 Black max i think it is....

found another number which is 8718337.. did a quick search and it pulls up a mid 80's 70hp block?!?!

 

[Melaney]

Re: (c) pozycjonowanie

Re: (c) pozycjonowanie

i found a part number of # 733201 which is for a mariner 75hp 1984

 

[Melaney]

Re: Mercury 850 help.. year etc..

Can you get a closer picture of the tag shown in this picture?

http://imageshack.us/photo/my-images/194/img1195s.jpg/

As well, to verify the s/n, do you see a disc like this anywhere on the powerhead?

http://img84.imageshack.us/img84/8224/391496208.jpg

Gerry

that first picture is a sticker saying its "equipped with perma spark plugs engineered by mercury marine"

i have found 1 welsh plug that looks new and has no markings on it...

 

[Gomer50]

Re: Mercury 850 help.. year etc..

Wow,Ive got something just like yours.Your Tilt and trim looks to be from the mid 80's and up.Powerhead looks like a 85hp late 70's early 80's.The good part is that most parts concerning the lower unit are all the same (waterpump/impellar).The gear ratio should be 2:3:1on the inline 4's.The lower cowling with the 90hp decal looks like it came off of a late 70's inline 6.The inline 6 gear ratio was 2:1:1 but looking at the lower unit you couldnt tell the difference.If I am not mistaken all 20 inch lower units from the 70's would fit all the way up to 1984.Even though most parts are still available online some are getting harder to come by and of course $$$$.Check your linkage and gear oil,unscrew the bottom drain plug on your lower unit and check for metal shavings.Your merc. looks pretty nice keeps the people on the lake guessing.My inline 6 90hp has a top cowling off of a 80hp,the wrap around is original 90hp the front cover plate is a Merc.140hp,1972 tilt and trim and a 1975 85hp mid section.Anyway have fun and happy boating.

 

[Melaney]

Re: Mercury 850 help.. year etc..

Thanks for all the imput guys.... im just going to find parts as i need them and hope for the best.... Local Merc mechanic confirmed it a bits-n-peices but couldnt tell me exactly what was what.....