is there a method of determining the year of inline 6 mercury 115 by the power head?

[mrtim42544]

I recently traded for what was advertised as a 150 tower of power but upon inspection there are a couple things confusing me. According to the serial number (4698423) it should be a 1977 model. The top cover has a 1500 sticker on it so it appears to be a 150HP. Looking at the power head, it has no distributor cap and all CDI ignition so I know it's not a 1977 model. The timing sticker on the power head says "M-115 timing" so I believe it's a 115 instead of a 150. I don't mind that it's a 115 but I would like to know what year model it is so I can get the correct parts should i need them down the road. Is there any way to get year model information from just the powerhead?

 

[flyingscott]

Take a pic of the powerhead

 

[mrtim42544]

No Title

Best I can do in the dark

 

[jimmbo]

You have a hodge podge mix of parts. In your first post you show the cowl complete and off the engine. In your last post the cowl, minus the wrap and front cover, is on the engine? The engine has an ADI ignition, so it is post 1978, it also has chokes, so it is pre 1984. It also it does not have a wiring harness connector on the starboard side of the cowl so it is post 1980. The engine block has been apart, evidenced by paint missing from bolts and a clean unpainted bolt, so who knows what hp you have really have. As for the cowl picture in your first post. Top cover could be, 1973 - 77, but I'm betting 73 or 74. The front cover, pre 1981, the wrap ????, the Decals on front and wrap, ?????. The lower cowl is 1981 or later.
Is there a plug on the block with a serial number on it? If so, does it match the one you have on the swivel bracket?

 

[mrtim42544]

Thanks jimmbo, it's a hodgepodge for sure. I can't seem to find a recognizable serial number anywhere on the block but I'll keep looking. So then, from the look of things, the powerhead is 81-83 and the midsection on down is possibly 1977? I did get to try it out before trading so I know it runs and has good forward and reverse gears, that's the main thing I suppose. They could have gotten the covers anywhere since so many will interchange. I'm installing it on a 1984 Cajun 19'6" bass boat so as long as it works out I'll be happy. I've only got $300 invested in boat, motor and trailer.

 

[Chris1956]

See if you can match up the block part number, with the year. It should be on the port side, near the seam of the crankcase cover and block. Clearly your midsection is 1977.

 

[merc850]

The wrap-around has been painted over and someone printed the Mercury decals using a design of their own so you "can't judge it by its cover"! You'll have to remove the plate that the coils and switchboxes are on to see the Ser. Nr. on the block.

 

[gm280]

WOW, seems a monster motor of different parts. Is the compression good? If so, I would try to identify all the different year parts just in case you ever need a replacement part. Other then that, all you can do now is run it. :noidea: