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1978 Johson 75HP Stinger Stator issue

M

Mick Stinger

New member
To All,

I know this topic comes up allot, I have searched through the forums and have not found a solution to my problem.
The problem was noticed when my tacho stopped working and volt meter was showing that it was not charging.
I put a meter on the battery terminals whilst the motor was running and showed 12.3 volts as per the volt meter.
I had a spare regulator so I changed this out with no success, I then did a diode test on my recitfier and confirmed that the rectifier is ok.
I then did a voltage test on the output terminals on the rectifier, I was getting erractic voltage readings between 0 and up to 19.8 volts.
I did an ohm test on my stator and got the correct reading of 1.5 ohms as per the service manual.
My last test I did and ac Voltage out put on the stator, this was giving me the same results on the ac side.
Would this indicate that the stator is bad?

Thanks for any help it will be greatly appreciated.
 
I believe that engine has a 6 ampere stator, a small 3 wire rectifier, but no regulator. Have you added a regulator?

Is the following the procedure that you're using to test the rectifier... if not, do so. Normally, if the tachometer starts to be erratic, or just quits, it's the rectifier at fault... unless of course the tachometer itself fails, a wire breaks, something of that nature.

********************
(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

********************
 
That's very true, Joe, I have many battery chargers that I've repaired with diode rectifier from. old GM alternators. People often destroy battery chargers as well as outboard rectifier this way.
 
Joe,
I meant rectifier not regulator, sorry about that.

With the rectifier did you mean diode test, when I put it on ohms I get no results at all.
In diode mode I get the following results

Black wire to the base and red wire to
yellow = zip
Yellow/Grey = zip
Red = zip

Red wire to the base and the black wire to
Yellow = 538
Yellow/Grey = 545
Red = 1009

Black wire to red lead on the rectifier and red lead to
Yellow = 534
Yellow/Grey = 541
Base of rectifier = 1000

Red wire to red Rectifier wire and black to
Yellow = Zip
Yellow/Grey = Zip
base = Zip

Regards Mick
 
No, I meant "Ohms".

I never cared for that long drawn out diode test, nor do I care for digital meters as I tend to obtain false readings.

I prefer a analog (needle) meter... doesn't matter if it's a $8.95 one or the expensive Snap On one that I have. With the needle movement, I am simply interested in whether I get a reading or not in that test... not concerned with what the needle reading is.
 
Thanks Joe,

I’m trying to get my hands on a dva so I can confirm the AC voltage from the stator.

Basically if the rectifier is ok and there is an issue then it can only be one other thing and that is the stator.

Regards
 
So an update on my situation,

I have now replaced the Stator with a brand new one and have replaced the rectifier as well, so now I have all new components on the charging system.
It has not resolved the issue of eratic voltage out of the the rectifier, and the voltage at the battery is eratic aswell. :mad::mad:
The taco is also not working, the signal voltage whilst idling is .2 of a volt and when the revs are increase it goes to .3 of a volt.
Engine runs fine just the charging is an issue is doing my head in.

Anyone got any ideas?
 
Do you encounter the same identical problem with the tachometer completely removed from the system... thinking a weird internal problem exists with the tachometer itself?

With everything replaced... the charging system returned to new, straight out of the factory condition, and assuming that the battery is not flawed in any way......... it leaves but one thought in my mind, actually an accumulation of thoughts along the same route.

Somewhere lies a broken wire, a badly frayed wire, a wire loose or attached to something it belongs not to be, a battery inaccurately diagnosed, something in the boat wired into the engines electrical system which should have been wired/routed through a fuse panel... OR... you have been pulling my leg all along as what you are explaining to take place really comes across as impossible.

Pertaining to the tachometer not working... to test.... tachometer dial set to #6 (6 pulse charging system), 12v applied to the proper tachometer terminal.... take the "gray" wire that attached to the tachometer "S" (sensor) terminal and touch one of the "yellow" wires leading from the stator, then the other yellow wire if no effect to the tachometer. If the tachometer is good, it should register properly when touching/attached to one or the other yellow wires.

I haven't re-read through all of the above posts but am assuming that you have checked the tachometer out in some manner?

I'm going to drop out of here as I can not think of anything further to say, and hope that one of out fellow members can and will jump in here with a cure.
 
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I think you have a broken wire somewhere, causing those erratic results. Like between the rectifier and battery. Or corroded or broken battery cables. Or a bad or loose ground (neg cable).

And yes I agree, the tach might be the problem. Try disconnecting it.
 
Joe,

Have only just got back into working on the boat after getting frustrated with it.
The Tacho I feel is definitely faulty, When power is supplied from the ignition it does not zero out.
The grey signal wire I'm getting 6 volts and increases with revs, needle does not move.
I removed the house battery and circuit from the system and just had the engine battery connected and the wiring harness for the engine.
Did not rectify the issue.
I have now disconnected the Tachometer, removed, cleaned and re-installed the battery terminals including the master switch.
Still have the issue but not as erratic as before, Still going between 11 volts and 14 Volts.
I have a video but can not upload it.

The house circuit i have checked and replaced all wires that look dodgy.

I think I still have a dodgy earth somewhere and now is just a matter of locating it.

The charging system is working but it is a slow charge until I find the fault.
 
I have read in other forums that maintenance free batteries can cause issues to CDI charging systems.
What issues do they cause?
I been running maintenance free batteries for awhile, had a maintenance free ALCO Calcium battery and have changed to a sea master Calcium MFM50 maintenance free.
 
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