Grabbing at Straws on HPDI

[florida_1959]

Ok I am at the end of my rope, grabbing at anything someone might throw out there. I have a 200 HPDI that wont charge 12.3 volts running (taken at battery with volt meter) Here is what I have done. All batteries and cables perfect, load tested and connections tight. Continuity from battery to starter and battery to block no problems. Replaced regulator/rectifier, no change. Checked ohm reading of stator wires to that of port engine, identical. Pulled flywheel to inspect for possible magnet or physical stator damage, none. Checked regulator ground wire, tight and secure. Continuity from reg ground to block no problems. Ran jumper ground from block directly to battery, no change. Trim, tilt starter all operate normally. Engine starts perfectly and runs great, no misses or alarms, just wont charge and tach fluctuates wildly at low and mid rpm (no actual engine speed change) so I know something is up with the electric pulse that drives the tach reading. I cant think of anything left to do. I know that red wires come from the back of the 80 amp fuses and go to the Trim and tilt relay, but I cant see how that would in any way stop charging if the relay was acting up? I can run the engines on "both" batteries and the battery will read 13.5 volts (coming from port engine charge), but as soon as I isolate the batteries/engines then the starboard battery is back to only 12.3 volts running at any RPM. Had it to the dealer and they are stumped, Im pretty much at a dead end.

[99yam40]

Did the shop or you test the lighting coil resistance and voltage out put like the manual says?
If so are they in spec?
Did you use the proper test equipment?

[GW267000]

You might want to check the tach its self. Had a similar problem not on a Yamaha, but the tach signal was in the voltage loop and was holding voltage down, disconnected tach feed and problem gone. Just something to check.

[jb123]

i just had the same issue with starting/charging my ox66s, was a wicked ground cable

[Finisher]

Couple of questions, What is the model number of the motor? What gauges do you have?(multifunction digital, analog, command link) Do you have individual volt meters? Do you have the isolator wire hooked up? What voltage do you have on the isolator wire?