4.3L OMC diagnosis.....

[lots of luck]

Well I am asking for a little help. Maybe a little back and forth dialog.

I have had a diagnosis on my boat, it has been determined that I only have 6 volts of power at the points in my I/O. Obviously it should be at 12 volts, hence the hard starting and weak spark (not much snap at all when plug is in boot and grounded against engine) at the plug. This is the 4.3L (GM) engine. I have not torn into yet and I have not purchased a OMC repair manual yet.

My question is can anybody help me diagnose the culprit?

For background I have replaced cranking battery, coil, plugs, points, condensor, rotor button, ignition switch, and distributor cap.

[Macgyver55]

Does your igntion system use a ballast resistor? If so, the ballast resistor reduces the current/voltage at the coil to reduce arcing on the points in point-style distributors. Usually on these systems, you will have full battery voltage only when cranking and a somewhat lower voltage when running. They are often a small white ceramic block with either 2 or 4 terminals on it. Could be the "cranking side" of the resistor is bad and not giving you full voltage when you are trying to start. After the engine starts it requires less voltage to run. Does it run ok once started, or are you unable to get it started at all? Did you check voltage while cranking or just with the key on? It would be a good idea to check both.

Also make sure the coil you purchased is made for a ballast resistor style system. (if you in fact have one)

Thats about all I have time for right now but should be a good place to start.