1976 Merc 700 70 hp cylider compression test help needed.

Hi folks,
I am looking to buy a '76 merc 700 70 hp 3 cylinder outboard but since all the lakes are frozen only thing I can do is runit with muffs and see how it starts and runs, and to do a compression test.
Is the compression test done with the engine at operating temp and only one spark plug removed (the cyl being checked) or all the plugs removed? How low long should I turn it over and what position should the throttle be in? And how do keep it from starting, will it harm the ignition systemto just pull the plug wires off?
What psi should the cylinders produce for a healthy engine and what percentage tolerance between readings?
What else should I look for on this unit and are they good outboards?
There is no tach on the boat, it is a bayliner capri 1400, it had force 50 on it the hull is in great shape is it too much motor for the boat?

What a slew of ??? OK guys have at it!
Thanks, Tappan

Re: 1976 Merc 700 70 hp cylider compression test help needed.

I would suggest that you try finding a lot of the answers to your many questions on compression testing by searching this forum first. Most of your questions have been asked and answered before and you would probably learn more by reading the many existing posts on compression testing than you would from a more abreviated response posted here. Then, if you don't find a good answer to a particular question, you can ask about the few questions you have left.

Having said that, check out the following links to get you started. Also, I suggest that you get a shop manual for the motor if you end up buying it. Good luck...

http://forums.iboats.com/showthread.php?t=188767

http://www.outboardrepairs.com/compression/