Year of 90 hp Mariner 2 stroke 3 cyl. o/b?

I have looked all over different sites that give you serial numbers to check and match to give you your year. There is a serial # on a plate externally on the motor but, it doesn't match at all? The number is 7214600. The only other marking on the motor is "power trim". I was told it is a 1996 or 97. Could someone be of service? Thanks.

Not sure what you have there.

That serial would make it a 1984, Canadian built inline 6 cylinder - so unless you lost 3 cylinders somewhere along the line, that's not a valid serial number for what you have

The 3 cylinder models started production in 1985 and are still being produced today - so that gives them a pretty wide range of "what it might be".

Since it's a Mariner (just a Merc with different paint/decals in this case) that probably leaves it somewhere between a 1985 and 1996 model (after 1996 they didn't paint up the 90's in Mariner colours).

If you can get a look at the side of the carbs (try the right side from the perspective of looking down their throats), that can give some clues.

If you see the casting number WME 3301-9012 that means it was definately built before 1995.

If you find a different casting number or can find an actual carb model number (which would look like WME 10 etc), post that up then it can be narrowed down to within a couple of years.

The serial should be "alpha numeric" similar to 0A1234567 (first zero may be omitted) through 0G1234567 etc and may be located on a welsh plug (silver disk the size of a quarter, similar to a frost plug on a car) somewhere on the powerhead itself...

WOW, now that's service. Thanks very much, I'll check all that out tomorrow morning. Appreciate it...

You might want to recheck that serial number, Because Mercury marine has that serial number registered as a 1984 MERCURY 9.8 M Model number 1010204.

Do you mean it's listed as a 9.8 HP? What does the M Model # mean? Thanks.

The number could be 7214500 instead of 7214600. It is also stamped Mariner International Co. Mississauga. Ont. Canada.

A 9.8 M would be a "manual start" (rope), twin cylinder.

I suspect the numbers you are finding the 721xxxxx are simply casting numbers, not the serial at all.

There should be a sticker on the exhaust housing. Stand facing the prop and then look on the right hand side of the leg - hidden up near where the bracket bolts onto the boat. Should be a little (almost) square sticker - black in colour with a serial.

Normally a zero followed by a letter and then a bunch more numbers...

Blackbart62 said:

The number could be 7214500 instead of 7214600. It is also stamped Mariner International Co. Mississauga. Ont. Canada.

Click to expand...

There you go, That looks more like it.

Engine serial number 07214500 Model number 7090624 1984 MARINER 90 ELPT.

Thank you very much. I guess I got the bums rush. The original owner told me it was a 1997. It has all kinds of recent shop receipts, ie: new plugs, tune-up, new stator and a couple other things. Is this a very good motor (in general)? Thanks.

The 3 cylinder 90 horse Merc's (which would include this Merc/Mariner) are definately the most popular motor in North America in the 75-125 horse class.

They didn't get that distinction by being problem plagued.

They are an excellent motor with good parts support. Although they have gone through a couple of changes over the years, they are still in production today - one of only three 2 stroke (non-DFI) models still built by Merc.

The fact that Merc is using it's carbon credits to continue to build this model for sale in the US speaks volumes to the loyal following amoung consumers...

I shouldn't have taken this guys word for much. He really didn't know what he had. I took the cover off the engine today and I see 6 spark plugs? So, is this still a 2 stroke motor? Do you have any feedback on the 6 cyl engine as well? Thanks.

Blackbart62 said:

I shouldn't have taken this guys word for much. He really didn't know what he had. I took the cover off the engine today and I see 6 spark plugs? So, is this still a 2 stroke motor? Do you have any feedback on the 6 cyl engine as well? Thanks.

Click to expand...

Here's a link for your engine parts, Take notice of the "inline" 6, Hopefully galamb could be of more assistance then I about the quality of this engine.

Good luck with it.

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=13290

Yes, it's still a 2 stroke, but a considerably less desirable model than the 3 cylinder version.

The inline 6 (tower of power) models had/have a fairly loyal (but small) following.

At least your model is (new enough) that it does have a Thunderbolt ignition instead of the distributor system on earlier inline 6's - but otherwise, mechanically it's a 1970's design, so the motor is "technically" about 8 years older than it's model year - that potentially makes some parts scarce.

However, the carbs are still 1970's era - old side bowls which tended to be leaky and inefficient, but kits are still available and they are still running strong on many older Merc motors that are still in use.

Again, because it has Merc's T4 ignition, all the ignition components are "regular stock", likewise all the water pump components are also available.

So while you could have done considerably worse, you did not get what was advertised.

On the plus side, the model had lot's of guts for a 90 (and has a better torque band then the 3 cylinder models). At the time this was produced Merc kinda (fibbed) a little when they stuck the 90 stickers on the side.

In order to better compete with OMC this model actually measured in the 100 to 105 horse range (BHP) which even in todays shaft horsepower rating system leaves it still a couple horses more powerful than a modern 90.

The motor was still worth buying despite the dishonesty of the seller...