115 hp merc cant charge batterie

My brother in law has a 115 HP mercury 4 cylinder,the problem is that the battery is not being charged ,it as a voltage regulator rectifier, front top.not sure on how to test. it is either a 16 or 24 amp?

Visually, the 16 and 24 amp regulators look the same. The 24 amp was an "option".

In any event, it's either working or not regardless of the amperage.

At idle either will put out 2 amps, at 1000 rpms you should see 10 amps.

To test for that you have (jump in) an amp meter between the red wire feed over to the starter solenoid.

So you disconnect the heavy red wire at the regulator (that goes to the solenoid) - connect the positive lead from an amp meter to the regulator, and the negative side of the amp meter connects to the red lead that you removed.

OR, you simply test the voltage of the battery with the motor not running, then test again with it running. If the voltage does not go up, then have the stator tested.

If the stator is ok, then replace the regulator...

could it be tested like a rectifier (diods) curent goes only one way? and for stator test?

ok galamb,i will test as you say. thank you.stil would like to know how to test the stator?

Scroll down to your motor. http://www.cdielectronics.com/downloads/Mercury_DVA.pdf