NO POWER TO PLUGS

[cvinson662]

hello everyone,
I have a 1995 mercury 40hp 2 stroke. one say the boat runs great. the next day, it would not crank. I checked the spark plug head boots with a volt meter and discovered the plugs were not getting any power. I tracked the power back to the wires that come from under the flywheel. so there are 5 or 6 wires that come from under the fly wheel that ARE holding power as they should. the wires run into a black box on the side of the motor. the same box provides power to the plugs. so it seems like this black box is the problem.no sure what it is or what it does. it is a sealed electrical type box. the next morning, found the warning horn to be going off and the sound of a sizzle under the console. I unhooked the battery at this point. anyone had any problems that sound like this or anyone know what might be the problem? I did use a different battery the day the problem started.
thanks!!!

 

[Barnacle_Bill]

Highly recommend you get a manual and start reading.

 

[quicktach]

Until you become proficient at troubleshooting and repairing problems, I recommend you get the motor to a good mechanic in a shop; particularly if you need the boat/motor soon.

 

[CharlieB]

When you used the different battery is there a chance that you happened to even touch the cables on backwards? Even a heartbeat is enough to burn out a diode in the rectifier, leading to letting smoke out of wires. A factory service manual will become your greatest friend. A color coded wiring diagram will quickly help you zero in on smoked wiring. Repost what color and where it is, we can help you more from there.

No spark needs to be troubleshot, start with the lanyard, is it in position correctly? Next step is to download and read the CDI Electronics Ignition Troubleshooting Guide available for free. It contains detailed testing for every ignition system to use your meter and prove what is causing the problem.

CDI Electronics Practical Outboard Ignition Troubleshooting

Remember, there is NO RETURN on electrical parts. Test twice, prove the fault, only buy what you need once.