Mercruiser GM Engine Block Serial Number

[CableGuy1978]

Hello all,

I am trying to locate my engine block serial number. When I bought the boat I was told it was a 3.0L 140 Hp. Of course, it is an inline 4 cylinder GM block. I have checked everywhere for a serial number, but the only thing I could find and positively identify as numbers and such was located on the starboard side of the block by the dipstick and oil drain.

The first and largest number I found was 2770087, which I thought was the serial number. I also found another number in that same area which was more difficult to make out, but I think it is 02679. Under all that it says "Hecho en Mexico" which I assume means it was made there. Have I found the serial number for this engine, or something else? I have my doubts as I seen somewhere else on the net where someone had the same number from a similar inline 4 GM block used by Mercruiser.

Any info is greatly appreciated. I am looking to replace my "Frankensteined" OMC manifold for a proper Mercruiser one so everything will line up properly so that my exhaust doesn't have to fill my bilge up with water and carbon monoxide.

Thanks folks,
Jason

 

[coheej]

Re: Mercruiser GM Engine Block Serial Number

The 2770087 is a casting # cast into the block. The second # most likely is a date code. That block was used in both 2.5l and 3.0l applications, so you can't tell from that #. The serial #'s on Mercruisers usually is stamped on a tag that is riveted to the block on the lower side edge of the bell housing mount area. A serial # was also on a label on the valve cover of some models.