How to test 2 wire voltage regualtor and or rectifier?

[mrteeman]

Hello

I've got a mercury 7.5 hp 1981. It's been made in belgium and got a bvoltage regulator with only 2 terminals.
look at http://www.**********/parts/search/Merc/Mercury/1982/1025502/BELGIUM%20ENGINES/parts.html
part #1

2 yellow wires from under the flywheel attach to the regulator, 1 wire to each terminal.
from terminal there comes a red wire and from nr 2 a black wire.

how do i measure/test it? i got 3 volts dc and about 13 volt ac.
and anyone got a clue how it's supposed to work ( i know something about electronics, but can't figure out how it's supposed to work)

regards t

 

[mrteeman]

Re: How to test 2 wire voltage regualtor and or rectifier?

url points to merucy part 95845

 

[Texasmark]

Re: How to test 2 wire voltage regualtor and or rectifier?

The yellow wires are ac voltage from your alternator under the flywheel. The red is dc out and black is ground reference...engine block/battery neg. The output voltage is dependent upon engine rpm and load. If you have a discharged battery, it will load the regulator and it cannot produce adequate voltage.....best thing to do is charge your battery before you put it on the engine.

Max output voltage for an unregulated alternator at wide open throttle (WOT) is 16v; if regulated usually 14.5 is max. When the battery is charging it will have more than 12v on it after it has charged up sufficiently to allow the regulator voltage to rise properly. Once the engine is stopped and the battery has had time to stabilize the battery voltage will drop to around 12.5 to 13vdc.

With that said, come back with what you were doing, condition you may have had, that could have given you a 3vdc reading.

The ac voltage goes into the regulator where there are probably 4 diodes in a full wave bridge configuration. If unregulated, that's all that is in there. You don't need fancy filtering and all for a battery. It takes care of all that itself. If regulated however, there will be the additional components for regulation, but on that small an engine you probably don't have a regulator. Regulators are on larger engines with larger alternators and are there to keep these larger alternators from overcharging the battery.

Mark

 

[mrteeman]

Re: How to test 2 wire voltage regualtor and or rectifier?

Thanks, this clarifies it a bit.

Got confused since most rectifiers i saw and know have 3 or more terminals. So mercury calling it a "voltage regulator" in their parts catalog is incorrect?

Regards teackele

 

[Texasmark]

Re: How to test 2 wire voltage regualtor and or rectifier?

The 3 terminal rectifiers are full wave, but not a bridge. Problem/difference is that the bridge uses the whole input winding to produce the output. The 3 wire FW rect center taps the winding so you only get half the voltage out. Both produce the FW rectification however.

Mark

 

[carholme]

Re: How to test 2 wire voltage regualtor and or rectifier?

Though you have not provided your s/n, here is the parts list for the 1981, including Belgium engines and you will see that it does have a V/R and rectifier. See items 16 and 21 under ELECTRIC COMPONENTS.

http://www.crowleymarine.com/mercury-outboard/297.cfm

Gerry

 

[mrteeman]

Re: How to test 2 wire voltage regualtor and or rectifier?

I don't have the rectifier on mine, can't find it. Haven't got electric start either. It seems by looking at the tap holes with thread for the start motor, there once was one, but flywheel hasn't got teeth for a starter.

serial # is 9263018 on the bracket, haven't checked engine block yet.
Haven't been able to date it more closely then 1980-1982...

i've got 2 thoughts now
-the voltage regulator is an AC voltage regulator, so you can use it for light bulbs etc, but not for DC equipment.
-the voltage regulator is a DC voltage regulator and the rectifier was removed by a previeous owner.