BF45 not charging

New to me 13' Whaler with BF45.

Previous owner had a rat nest of wiring for bilge pumps, bait pumps, radio GPS etc, and the battery was just loose in the stern. I'm still in the process of cleaning up the wiring, the battery is now secured in a battery box in the correct location and the ONLY connections to the battery are the positive and negative heavy leads to the starter.

When the motor is running at ~2000 rpm there is no increase in voltage. The tach is working so I assume the coil is good. Pulled the rectifier and using a multimeter set to Diode, I get open circuit between white and all three grey wires, Open between white/black and all three grey wires, dead short between white and white/grey, and a dead short between two of the grey wires. Bad rectifier, right (want to be sure before ordering a new one)?

Also, the White wire has constant 12V even with the ignition off. Is this correct?

Thanks for any insight!

Matt

The tests for the rectifier/regulator should be in the resistance mode. The values will make a difference, depending on which leads the red or the black go to. Reversing will most likely provide a different reading.

I have found, that if you measure a good ac voltage on the grays leads coming in and only battery voltage on the output leads, then you have a bad reg/rect.

Yes....the white lead should have 12v all the time....as long as the main fuse is good. Another part of that lead provides the power to the keyswitch.

Mike

hondadude said:

The tests for the rectifier/regulator should be in the resistance mode. The values will make a difference, depending on which leads the red or the black go to. Reversing will most likely provide a different reading.

I have found, that if you measure a good ac voltage on the grays leads coming in and only battery voltage on the output leads, then you have a bad reg/rect.

Yes....the white lead should have 12v all the time....as long as the main fuse is good. Another part of that lead provides the power to the keyswitch.

Mike

Click to expand...

Thanks Mike. Rectifier on order and I spent the day cleaning up the rats nest. Should be good to go by next weekend!

Matt

I finally got a decent (legible) wiring schematic from Honda.

Can I use the keyed power from the remote to power my marine radio and nav lights? Looks like W/Bl is "battery" (with key on) and Bl/Y is "load" (with key on). I'm guessing "Load" would be used for accessories like nav lights? "Battery" for a dash voltage gauge?

That is not good practice.

That lead shod provide power to motor related items only.

If you have vhf, horn and other items ...they should be separately fused from a fuse panel or separate runs directly to the battery.

Mike

hondadude said:

That is not good practice.

That lead shod provide power to motor related items only.

If you have vhf, horn and other items ...they should be separately fused from a fuse panel or separate runs directly to the battery.

Mike

Click to expand...

Thats what I figured, just got excited about NOT running another set of wires. I'll run a separate fused + and - to my switch panel.

Everything that I have read about the unreliability of testing the Honda regulator / rectifier is true.

I measured the resistance and diode tested every which way through the rectifier and got some very unexpected results, open through the two gray coil leads, resistance both ways through the tach lead and one of the coil leads (but not the other), dead short through white and white/black and one way resistance from ground to one of the coil wires (good diode).

Bad rectifier? Bought a new one and everything metered exactly the same:rolleyes:

Reinstalled the old rectifier to do some more testing.

12.3 Volts at the battery (off and at ~2000 rpm)
Tach works
Oil pressure light illuminates (runs on AC from the coil)
>20Volts AC at the coil (two grey wires) @ ~2000rpm

Got to be a bad regulator/rectifier right? Yep. Installed the new reg/rect and now charging nicely at 13V at idle

Back to the lake tomorrow!