Need help with a motor I am looking to buy

[Mike1985]

I am looking to buy a 100hp evinrude outboard.
The compression is as follows

70psi 71psi 80psi and 89psi

Also the owner is unsure of the year. He gave me the model # and serial # and both come up different when I search it.

serial # is J 07761 and model is 100293R

The guy selling this motor said his boat does 45mph with this motor and runs great for him. He is just upgrading. Can anyone help me out finding out what year the motor is from the model and serial #'s and give me input about te compression?

[boats.net]

Make sure you are taking the compression properly, as all the cylinders are within specs of each other, but they are unusually low. This motor is a 1972.

[billnorman]

The cylinders are out of specification, with a 19PSI difference which exceeds 15% in my humble opinion. Use a screw-in compression gauge to make sure you have an accurate reading. It is a pretty old motor and if you have to fix it, it will be difficult and expensive, as many bolts tend to seize up and snap off on motors that old.