What is the shaft diameter at the coupler end of the Merc alignment tool. Mine may be homemade and is 1.010".

ttt

First two and a quarter inches is one inch in diameter.
Second two and a quarter inches is one and three sixteenths inches in diameter. The rest (17 1/2") is one and three eighths inches in diameter. Now get out there and save a couple bucks.

I'm 10 thou over 1 inch,how close did you measure?

Mine measures 1.010" also. That is my Merc tool.
Just a tip:
I made a couple of stubbies 1.010 and 1.000, along with a new tool at 1.000

I use the stubbies to see if the alignment tool will even go in the coupler. They are only a couple inches long and checked for fitting by reaching over the back of the motor. IF the standard 1.010 does not go in, then i check with the 1.000. If that one does not go in, then I check the couple close for wear. If both stubbies do go into the coupler with a good straight, non bell mouthed feel, I can use the undersized alignment tool to get the alignment close if I am having trouble with standard one to work. Then switch to the standard and fine tune.

I somehow doubt Merc makes their alignmet tools using a Stanley tape measure.

Thanks,you are the man again.