2004 3.1 225 hp possible stator issue

[Fishinsalt6]

I have a 2004 Stratos with a 225Yamaha 3.1 liter. The problem is constant dead battery. I have a new group 29 battery and a new 3 bank charger. All are good. I put all leads from the boat and engine to the positive terminal and disconnected all from the negative side. I clipped one end of a test light to the negative post and touched all wires that would go to the negative post and test light lit up. I Isolated the positive big wire and disconnected it from the battery and left the boat side positive wires hooked up and repeated the test. The test light did not light. I then only hooked the positive wire to the engine to the engine on the positive battery terminal and repeated the test and test light lit up. Could a stator or regulator causing the battery to die overnight . By die I mean only have enough voltage/amperage to barely work the trim/tilt ? Any suggestions would be helpful. If I have left any info out let me know and I will add that . Thanks Rick

[99yam40]

I would use a DMM set on amps/miliamps to find how much is being pulled with key off.
may have to disconnect wires at different points to isolate exactly what is drawing the current.
Lots of stuff on modern motors

[scofflaw]

My boat does something similar if I forget to turn the battery switch off. Not sure what a 3 bank charger is supposed to do with your configuration. Chargers need ac power. Wire in a battery switch and turn it off when your done using the boat

[rodbolt17]

the rectifier could. the stator no.
however most ECU's and some gauges and devices have a constant drain anytime the battery is attached.

[FabricGATOR]

99YAM suggests to use a DMM to read the current draw, what you did with the light, repeat with a digital multi meter (DMM) to get the real parasitic drain value that you see with the test light bulb.

RodBolt says that the rectifier (if faulty) can cause drain (probably an internal diode fault) and that the ECU and some gauges will draw power even with ignition off. This should be milliamps of draw (think like the slight draw of your car stereo to maintain your preset stations and the clock) That ECU and Gauge power draw should not kill the battery in weeks, let alone overnight.

Sometimes the battery near the end of its life can seem to operate just fine all day but may not hold a charge over time.
Check the electrolyte level often in FLA (flooded lead acid batteries). It should always be over the plates. Only add water (best is distilled water). Only top up to fill line with water AFTER the battery is fully charged. (add water to just over the plates before charging, then to fill line after charging)

Internal resistance.
Charge the battery and either let it sit for a few hours or hook up something to burn off what is called the "topping charge". (A headlight bulb for two minutes) then let it relax for two minutes and then record a voltage reading. Check it again over a few nights and see if it falls off.

But get a DMM and record / report the amperage (or more likely the milliamperage) draw first thing to start.