What year 115HP Mercury Outboard?

[Racer67]

I just bought a 20' CC with a 115HP Mercury Outboard. The hull is a 1988, but the guy said he wasn't sure on the engine year. I looked at the Serial Number, but it's just a sticker and could only make out a few digits that appeared to be in the middle of the serial number, so that wasn't much help. I took photos of around the engine in hopes someone can help identify the year or at least the range. I have to put a new lower unit on it, so it's pretty important. haha.

Any help is appreciated!
Thank you!!

 

[Chris1956]

Well, that is an inline 6 with ADI Ignition. That places it between 1979+1/2 and 1987. Show us the power trim, and the carbs.

 

[Racer67]

Thanks for the reply. These were the only pics I took. The boat is in a storage place about 30 minutes away, so won't be back over there for another day or two.
Does 1980-1987 all have the same lower unit? I was also told that the 90HP and 115HP are the same lower units?

Thanks!

 

[Racer67]

I found this one: http://www.ebay.com/itm/1982-mercur..._Accessories_Gear&hash=item27f85ac44d&vxp=mtr Will this work? How do I go about measuring the shaft? Do I need to take the lower unit out and measure or is there a way to do it while it's installed? I just want to make sure the new lower unit will match up and I don't spend $300 on something that doesn't fit.

Thanks guys!

 

[roscoe]

Really can't tell if that one will work.

The term "shaft length" is misleading.

You don't actually measure the drive shaft.

You measure from the transom mounting bracket, to the anti cavitation plate,
the area between the 2 red lines in the photo below.







The standard length are below.
​

Short:	15"
Long:	20"
X-Long:	25"
XX-Long:	30"

The ebay seller, may not even know the correct shaft length.
I have seen many listed with very odd numbers, that were never even made.

Since the seller may not know, then yes, that is a time to actually measure the shaft length from
the top of the water pump, to the top of the shaft. Then compare that to your own measurements.

 

[Racer67]

No Title

Thanks for the reply! I just went and pulled the lower unit, came out pretty easy, so that was nice. I'll measure the shaft and compare it that way. Would there be any markings on the lower unit to tell me the year or anything so that I can be sure I get the correct one?

Also, I attached a pic of the carbs.

Thanks

 

[Chris1956]

OK, Is your power trim unit three cylinders, two cylinders or one cylinder? Is there an external Power Trim pump in the boat?