Rectifier Regulator 225 V6 Looper 1990

"I am getting strange behavior

"I am getting strange behavior from my GPS it powers on then flutters on and off until I pull the power plug. The Same day I had a terrible time starting the motor - Ran both batteries almost to zero before she kicked off. I thought the GPS problem was related to low voltage. I didn't shut the engine down for fear of not restarting so I don't know if the gps would have run normally with the engine not running. Now with more time to ponder, I am thinking that the GPS is reacting to AC in the power from a bad rectifier. I have recharged the batteries fully and will do some more diagnostics.

How do I eliminate the rectifier from consideration or verify it is working properly. Other testing ideas would be appreciated. Also is there a part number to year-model application cross reference on ALL motors that use a particular part number. The rectifier regulator for my motor is omc 583689. Searching for parts prices I found the part number on numerous years and models, especially with the CDI replacement part which replaces half a dozen omc part numbers.."

was the motor charging the boa

was the motor charging the boat batteries when it was running?
Do you have the correct spark plugs in that motor?
The correct ones have induction suppression QL77JC4 for example for use with gps and other sensitive electronic equipment

Back home I tested the batteri

Back home I tested the batteries they were not badly discharged - so I think it is safe to say that the motor is charging. I also have a volt meter which seemed to be reading the usual 13+ volts while running. The plugs have been in the motor for a long time and never affected the GPS before. I am pritty sure they are the resistor type. I'll check the numbers though.

When I reinstall the batteries I will see if the gps works with the motor not running - then start the motor and see what happens. I am hoping this all may be related to the badly discharged batteries. I read that the regulator needs battery voltage on the purple lead to work. Book didn't say what happens when the battery voltage is low. Thanks for the reply.

Finally back on this. I charge

Finally back on this. I charged and tested the batteries (specific gravity). They both took a full load of electrons. Tested GPS and everything else with the motor not running. AOK. Started the motor with fingers crossed and the rectifier regulator seems to be working fine. I guess you need some minimum battery voltage for the charging system to work properly. If not you may see some AC coming on the line and disturbing the electronics. Interesting!!!!!

"Hi Mike,

With engine runni

"Hi Mike,

With engine running, measure the AC voltage with a regular VOM on the yellow wires from the stator. They should go to a terminal block on your motor. Should be 25-30 VAC.

Also, you can disconnect the large red wire that comes from the reg/rect and goes to the starter solenoid. Disconnect that, and insert an ammeter temporarily. Check for charging that way.
Also see here....http://www.marineengine.com/discus/messages/12478/292044.shtml"