Mercury Mark 55 info needed.

[landlubber1]

I have a Mercury Mark 55, 4 cylinder. I am having trouble with the Serial number. It looks like the plate was damaged and all I can see for sure is the last 2 numbers which are a 89. Is there a second serial number location besides the plate on the front of the mounting bracket. I have no idea how old this motor is, or what is the horsepower. Any info would be very helpfull.

 

[Laddies]

Re: Mercury Mark 55 info needed.

Most were marked on top of the powerhead by the exhaust cover, if not the engine has a lot iof distinct thing that will help identify it--Bob

 

[WillyBWright]

Re: Mercury Mark 55 info needed.

1958 would get you in the ballpark. I believe they produce 40Hp. Never figured why they called it a 55. It Ain't! Later incarnations produced 40, 45, and 50. Never 55.

 

[Chinewalker]

Re: Mercury Mark 55 info needed.

The Mark 55 was built from 1955 to 1958. As Bob pointed out, the serial will also be stamped into the block on top.<br /><br />It did indeed produce 40hp.<br /><br />Willy - it was referred to as a '55' because it came out in 1955, and the Mark 58 was the same way - 1958. The last digit rule held true for several models, Mark 25 (first year 1955), Mark 28 (1958), and Mark 78 (also 1958). It held for year of introduction of a model - not necessarily year of manufacture and (as was often the case with Mercury) didn't hold true for all models... An 'A' was added to the model number for 1959 to designate Anniversary year (20th for Mercury).<br /><br />- Scott

 

[landlubber1]

Re: Mercury Mark 55 info needed.

Thanks for the info one and all. I at least now know where to look for the serial number and have a good idea what I have. It seem it is a bit of a antique. But it probably will run better than what on the market today.