Mercury serial # 1B010234 what year is this motor?

Question edited for a lot more clarity.

They are normally listed by HP.

https://www.google.com/search?q=mercury+outboard+serial+number+lookup

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Only things I could find ...

1. S/N beginning with 8075603 , 2.2 Hp was 1984
2. There was a different reference that different countries could have different serial number series which complicates matters.
3. But there was also a reference indicating for outboard motors ... that the nameplate which has the model and serial number ALSO had the year written down ... the last 2 digits of the year in a box in the lower right hand corner

You'll find a tag on your bracket.
The upper numbers you'll find your serial number,
Then in the 'box' just below the 4 digits indicating the production year.
Is it a 2.5Hp, or 2.5liter? Your serial is in the V-6 2-stroke 135-175 Xr range...

Finding my Year for mercury outboard by serial number
Mercury Outboard Serial Number Guide

Locate the serial number plate by looking on your motor's transom bracket; the plate will have "Mercury Marine" written on the top. The serial number is the top number on the plate. The number directly beneath this is the year it was manufactured.
The year will be determined by the number of cylinders,,,
A 4 cyl. is a 1986 .
75 - 4 Cyl. 1986 ELPTO, ELO A197882 - B249479 = U.S. Serial Numbers A70708 = Canadian serial numbers

go google and type in--- mercury outboard serial numbers -- there are sites that listhp against serial numbers against year of manufacture
while you serial number may not be listed they state that the beginning of the number to the next changing number is the year of make
for example ---4261012 to 4302999 ( next number 48103665,year 2002) may be year 1999 so your number would be a 1999 model
The information provided will take a bit of understanding as it appears that the manufacturer changed the method a number of times
talk with a mercury / mariner service shop as they will have the information on hand

the serial number begins 2487558 and continues past 2491265 and as the beginning serial number denotes the year , your engine is 1969 model
it shows as a 2 stroke with auto oil injection
check the heads
if the plugs are in the flat of the head and there are no rocker covers it is 2 stroke
talk with a mercury /mariner service center

According to i-Boats, "Nothing in the Mercury Mariner Outboard engine model numbers or serial numbers provides year information directly.
The first serial number sold in a year becomes the beginning serial number. Serial numbers between that year's beginning serial number and the next fall into the same year. Search for your engine horsepower on the Mercury Mariner serial number year chart located here to find the beginning serial number for the range that includes your engine." Your other option is to take the serial number to an authorized Merc marine eager and they can look it up for you.

That serial number is also not found in the Mercury Marine Directory. Are there more numbers or characters?

call mercury outboard they can tell you the answer to your question