Mariner 75HP Rectifier?

Bill3434

Petty Officer 1st Class
Joined
May 29, 2011
Messages
398
Re: Mariner 75HP Rectifier?

I really appreciate the help everyone. The black wire that is broken is definitely connected to another terminal.

I had continuity with the two yellow wires from the stator, but none when each was grounded. The resistance, if was done correctly, was .001-.05. Specs call for .19-1.7

I have someone coming over later in the week that knows a lot more about motors and does side jobs, to help. I'm just wondering now that if it is the stator or trigger, not sure what wires go to what, instead of the rectifier. Unless the broken wire fried the rectifier??

I remember getting voltage from the gray tach wire, around 7.5-8v at idle.

I'll keep ya updated and hopefully I can get it done before I leave for fishing week!

Jeff

Sorry I can't help you with the tach voltage but from what I understand a bad stator can effect your tachometer. Not sure if your ground wire would effect your readings on your stator; if it would your readings most likely be lower than what your have now. It almost sounds like some of the insulation on the windings may have melted and shorted your windings therefore reducing your voltage. I just had my AC/DC circuits course in computer science, paying off already. hehehehe. Have you asked your local boat shop if they can test your rectifer if you bring just that in? Hate for you to waste money on something you can repair yourself. Hate it even more when a man's fishing trip is sidelined. Bin there, done that and darn sure didn't like it either.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Mariner 75HP Rectifier?

I had continuity with the two yellow wires from the stator, but none when each was grounded. The resistance, if was done correctly, was .001-.05. Specs call for .19-1.7

Your reading may differ depending on what scale your meter is set to.

Neither yellow lead should read to ground.

The black wire is simply a 'spare' ground from the stator frame to the motor and is NOT found on but few stators, it is not necessary.

Set your meter to AC Volts and the scale to 250, tie into both yellow leads with the regulator connected. Start the motor on the garden hose and check voltage at idle and what it rise when you fast idle. If you are getting readings then chances are the stator is good.

Now disconnect the meter and switch to DC Volts and connect to the battery, run the motor and watch the voltage, if NO rise at fast idle then order a rectifier.
 

njbadboy

Cadet
Joined
Apr 29, 2012
Messages
16
Re: Mariner 75HP Rectifier?

Thanks CharlieB....In doing settinh the meter on AC at 200 (no 250) I got a reading around 12.5v one one yellow and less than that on the other yellow (around 7-8v). As idle increased, so did readings.

No yellow read to ground.

Change to DC and connected at battery. Consistent read at 12.5v, even at Idle.

Ordered Rectifier.

Thanks to everyone with their help.

I'll post with an update when new rectifier installed...

Jeff
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Mariner 75HP Rectifier?

The test should be BETWEEN both Yellow wires to get AC Volt input to the Rectifier.

Test twice, once disconnected, then again connected.

Then disconnect the Red wire from the Rectifier, switch your meter to DC Volts and test the Red rectifier lead, reconnect and test the Red lead again.
 

njbadboy

Cadet
Joined
Apr 29, 2012
Messages
16
Re: Mariner 75HP Rectifier?

I received my new part (rectifier from Sierra). It has the same wires;two red, two yellow, a gray wire, but the new part has a black wire added. Do I need to ground this and if so where?

Heading out to Smith Mountain Lake Sunday.

Thanks,
Jeff
 

njbadboy

Cadet
Joined
Apr 29, 2012
Messages
16
Re: Mariner 75HP Rectifier?

The ground wire had to ring ends, just not sure if I should attach one end to the bolt for the box and the other end somewhere on engine?


Thanks

Jeff
 

njbadboy

Cadet
Joined
Apr 29, 2012
Messages
16
Re: Mariner 75HP Rectifier?

I just off phone with Teleflex Marine (Sierra) who advised to attached one end to the mounting bolt for the rectifier and ground other end out. Thanks!

Thanks to everyone who helped me as well!

Jeff
 

quicktach

Petty Officer 1st Class
Joined
Aug 24, 2012
Messages
394
Re: Mariner 75HP Rectifier?

Check the rectifier. I once had the 80HP Merc engine and the tach went the same way. Turned out replacing the rectifier did the truck!
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: Mariner 75HP Rectifier?

Yes the black wire needs to be grounded to the block, usually on one of the bolts that mount the regulator/ recitifer. Take a small battery charger along on the trip, as it might save a early return home. As stated before , the motor can be run as long as the yellow wires are disconected and insulated. JMO
Oldman570
 

njbadboy

Cadet
Joined
Apr 29, 2012
Messages
16
Re: Mariner 75HP Rectifier?

Well guys back from my trip, although the fishing was tough, there were no problems with the outboard. The volts read between 13.7-14v while running at 75-80% throttle, and charged the battery the entire week, no need for the backup charger.

Thanks again for everyone's help! Hopefully this post will help someone else out in the future.

Jeff
 
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