1995 175hp - Tach works but not charging batteries

[nphilbro]

Narrowing previous thread to single question. Model J175EXEOM
Motor starts well, goes into quick start at +/-1000-1100 rpm then drops to around 700-800 rpms and very smooth.
This was the reading TODAY on my outboard tach, set to 6P.
Rectifier is water cooled style and there is no terminal block.

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[FONT=arial, helvetica, sans-serif]Good tach reading but non-charging condition seems to be the inverse of everything I've ever read about rectifier issues on these charging systems.[/FONT]

[FONT=arial, helvetica, sans-serif]I hooked the multi-meter red probe between the plug and jacket of the red FUSE+ connection (which terminates with all the red+ wires at the battery side of the starter solenoid), clipped the black test probe to the common case ground bolt shared with other component grounds.

Turn key to "On" voltage drops from 12.7 to 12.63 at the battery. Powered connections now are the AM/FM stereo(standby mode), alarm, and gauges: tach, battery, hour meter.

Start motor: Voltage at the battery drops [/FONT][FONT=arial, helvetica, sans-serif]from 12.7 to 12.3, returns to 12.5 quickly, climbs to 12.57 by the time the quick start routine complete.

Voltage of the purple+ wire from the key switch to key switch ground is the same as the battery terminal voltage. Voltage at the Solenoid+
to case ground same as purple+ to ground regardless of RPM (up to 2k on muffs).

I never get anything over 13+ V at the battery or anywhere in the system with motor running.

*Diode check at rectifier [/FONT]with all wire plugs disconnected from stator, battery, tach and engine not running.(Neither has a gray stripe, gray wire comes directly out of the pack)
[FONT=arial, helvetica, sans-serif]yellow wire "1" reading one direction.
Yellow wire "2" no reading

Another question: are these 35A stators 2 phase or 3 phase? I could run another easy diagnostic test if I knew the answer.[/FONT]


Two batteries on a Pergo 1 Both 2 Off switch. Well maintained, kept on Marine two bank charger (15A max auto switching to 13.7v float). Battery One: 12.7V resting voltage 24 hours off charger, Battery 2: 12.8V resting/24 hours. Batteries are a year old, distilled water added occasionally as needed through the year.

 

[boobie]

Did you ever put it in the lake and run it WOT and see what the voltage is ??

 

[Vic.S]

I never get anything over 13+ V at the battery or anywhere in the system with motor running.

13 volts is a bit low! You wont be effectively charging the battery at that level.

Another question:are these 35A stators 2 phase or 3 phase?

Rectifiers are either single phase or three phase.
If there are two yellow wires coming from the stator it is single phase.
If there are three yellow wires it's a three phase rectifier

You only mention two yellow wires so its a single phase rectifier.

I don't believe you can easily test a rectifier/regulator other by checking if its working or not. It's easy, although a wee bit complicated, to test as simple non regulated rectifier

( when I say yellow wire I include yellow with blue or grey tracer)

 

[nphilbro]

Well I've been doing a lot of research the past month now that good fishing weather is behind us. So you are, of course, correct, Vic, the two wire stator on this motor is single phase and the battery charge circuit is completely independent of the ignition/timing circuit.

The tach worked, I'm guessing, because the diode bridge burned out opposite that connection point. I wanted to test the charge circuit so I bought a 600V/45A rectifier from Fry's and mounted it to a heat synch, connected the two stator wires and the +/-. Tach worked again and battery terminal voltage read 18-19V. This only confirmed that unregulated charge was coming in and the tach was reading correctly so shut it down after warm up RPM dropped, before roasting the batteries.

I reverse engineered a new one and found some serious fatal flaws in this design:
The diode bridge wastes about 40W (converted straight to heat) which translates to a voltage drop of 2 to 2.5v,
SCRs also impose a great deal of resistance against the current even on the open gates.
This all requires a great deal of heat syncing - hence the liquid cooled case design.
Ground is internal to case - bolts become anodes and corrode, ground connection diminishes and eventually unit fails.
The bridge rectifier I purchased was $6.95 and is the part of the circuit that most commonly fails when open circuit voltage blows through.
35A in single phase is a bit optimistic but 25A at 4500rpm seems plausible, 35A would unlikely through a single side of the circuit, even at 6k RPMs.

This is the board, sans rectifier. The entire unit was built to dissipate heat.


Here's my ugly mock-up circuit that I tested on the motor. It worked..voltage was a bit high @15.5-16.5V (need to adjust the gate resistance a bit). I was planning on running the stator wires through the control cable tube and cool it it's own heat-sync way from the motor.




I was all good to start a installation build on this when I discovered these new MOSFET regulator rectifiers. They are much newer technology than the 1960's era transistors in the original R/R unit. They also run VERY cool compared to SCRs.

They come in many form factors and plug styles. In the case of a short of open voltage they shut off and continually test for correct operation status.

http://www.rmstator.com/en/catalog-...tage-regulator-rectifier-rm30504h?filter=true

The gray tach wire would just splice into one of the yellow wires. Red to battery, black to ground. CDI eliminated the violet on later versions, added a ground wire. The original (empty) case would have to be installed into the block then I'd have to find a better location for the MOSFET unit to get it some cooling.

 

[nphilbro]

Here's a pic of the one I'd like to use. 1/2 the price, *Should* meet or exceed factory spec. Tired of losing a $250 part every time a ground gets interrupted due to connection fatigue due to trailering and using it in rough water every weekend 6 months of the year. At least I would know there's a connection somewhere that needs to be serviced prior to a complete part failure.They cost from $85-$125 for genuine Shindengen mfg. part depending on seller and harness chosen (I'd just build a harness).

SHINDENGEN FH020AA REGULATOR /REPLACES FH012AA

 

[jstpie5]

I know this thing is pretty old, but did you ever get your regulator/rectifier circuit to work properly? what about the Shindengen regulator?

Can you post the parts you used?

I have a 1995 225 HP Johnson that has a bad regulator. I'm cheap and trying to find another/better way to 'rectify' this issue.

 

[GA_Boater]

I know this thing is pretty old, but did you ever get your regulator/rectifier circuit to work properly? what about the Shindengen regulator?

Can you post the parts you used?

I have a 1995 225 HP Johnson that has a bad regulator. I'm cheap and trying to find another/better way to 'rectify' this issue.

Start a new thread, The OP hasn't been here in a long time.

Closed,