Re: ? on powerpack
You need a special multimeter to test them. What you can do is go to the library and check out a service manual or buy one here, then check the other ignition components. If they all test OK, then it's reasonable to assume that the switchbox is bad.
In the defense of the expense of taking it to a pro, most can diagnose an ignition problem in less than an hour. If it is the switchbox, diagnosis and replacement might be just one hour. That eliminates the possibility of buying a new switchbox and having it not be the problem. They're not returnable. Best to take it to a dealer of the brand of motor (Mercury in your case).
Before taking it in, see if there is any spark. Pull the sparkplugs, connect them, and lay them against the block. Have someone twist the key and look-see what you have. Don't put your face in the path of any spray that might come blowing out the sparkplug holes. It could ignite. Yikes!
