Outboard electrical problem?

[Mugsaway]

1991 Evinrude outboard, 40 hp 2 stroke

I need input as to what the following problem may be.....

The cranking battery went dead so I switched the wires to the deep cycle battery to start the motor. Went fishing and noticed the voltage gauge on the console read 17-18 volts while running at high speed and electrical accessories from the dash (bilge, depth finder, aerator) no longer worked. I bought a new cranking battery and re-connected it to the motor and the voltage meter still reads 17-18 volts and the components still do not work. Could this be the voltage regulator on the motor or other some other component? Could this have happened because the deep cycle battery was used instead of the cranking battery?

[Valv]

I believe it is the voltage regulator which built into the rectifier. I don't think it had to do with battery type, but it might be the cause of your bad battery

[Mugsaway]

What is a rectifier and where is it? How do you test it? Is this something the average joe can do himself or should I bring it in?

[boatfixer]

I'm going to guess that when you reconnected to the other battery, you may not have reconnected the power for the accessories. With a good regulator, you should read about 13.6-14.2 for voltage. 17 is too high. It does sound like your rectifier/regulator is bad. I would first make sure that it has a good ground. Excess voltage is "bled" off to ground.

[TimR]

Quote:

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What is a rectifier and where is it? How do you test it? Is this something the average joe can do himself or should I bring it in?

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Looking at a parts diagram for a 91 40hp, you may have an unregulated power supply. The rectifier converts the AC current to DC, and the regulator restricts the voltage above a certain amount.

OMC engines of this vintage often had unregulated power supplies. For example, the 90hp can come either with simply a rectifier, or a reg/rec - which is water cooled and mounted in the block.

You may have never seen a high voltage reading before because the battery was partially discharged. The meter will not show a charge above 14 volts if the battery is partially discharged and is actively charging. Once the battery is at capacity, then you will see the 17-18 volt readings on the meter.

I have the same unregulated power supply on my 90hp, and when the battery is fully charged, you get 16-17 volts.

If you shoot me an email, I'll send you a link to a site that has parts breakdowns of OMC motors. I would never buy something from that site, but the online parts are nice.

Tim