Smartcraft data bus fuse

[ganier57]

I have a 2006 Mercury 60 HP 4 stroke EFI outboard that is blowing the 15 amp Smartcraft Data Bus fuse. The voltage regulator / rectifer has been replaced and the fuse still blows when the motor is revved up to about 2500-3000 rpms. The battery is not charging when the fuse is blown. Any help with this is appreciated.

 

[alldodge]

Only thing I can think of that would draw a slight bit more current as rpm increases, is the coil. That said its hardly ever the coil

 

[dingbat]

Looking at the harness docs, I’m willing to bet the fuse blowing at a certain rpm is a coincidence.

Data communications use mA of power but documentation shows the harness also supplies a 15 amp, key switch controlled “accessories” power harness through a 10 pin connector. Who knows what’s plugged into this feature.

I would locate and disconnect the connector to see if the problem goes away. While your at it, but a meter on the power pins in the connector. Run the motor up to 2500 - 3000 rpm and see if the voltage spikes.

 

[ganier57]

OK, I figured out how to test the stator output and got a reading of 26.4 v at about 850 rpm which according to the tech I talked to that is good ( should be between 15 - 30v ). I have checked and cleaned every connection and installed a new voltage regulator / rectifier. It was charging good at about 1000 rpm but blew the 15 amp smartcraft data bus fuse again and quit charging, don't know if it fried the rectifier again. Does anyone here know how many amps the electric fuel pump should draw ?

 

[alldodge]

I don't know, but blowing a fuse means its pulling to much. The normal charge voltage at the battery is no more then about 14.5V