Re: 72 Johnson 100 not running good
The first thing I would check are the two sensor wire's going to the the timer base. If you look on the right side of your engine you will note that the timer base, and throttle linkage are hooked together with levers, and rod's. Disconnect the remote throttle cable so that you can easily work the linkage by hand. Looking at the timer base under the flywheel, you will see it rotate back, and forth as you work the throttle by hand. You will see a lever on the timer base where the throttle rod snaps in, this is where the sensor wires are rouhted. Every time the timer base is rotated back, and forth these wire's make a sharp bend, they can break right at this bend. Unplug the sensor wires, and hook a ohm meter across them. Pull on the wire's, and see if the meter goes in, or out of contact. If one, or both wire's are cracked, they can go in, or out of contact depending on throttle position. When they break, and make contact with the engine running it will sound just like you switched the key off, and on just as you discribe. This may not be the answer to your problem, but that is where I would look first.
