Charging problems on a '91 120hp Force

orignagah

Recruit
Joined
May 30, 2012
Messages
4
Right off the bat i saw the reg/rectifier looked burnt, so i ohm tested the stator and it checked out ok. Ordered a new reg/rec from pro marine and they sent me a mercury reg/rec #5279 (TRR3072-1060 is the number on the unit itself) that doesnt look like the old one. the old one looked more like the one here

http://www.powersportparts.net/SPORTS-PARTS-VOLT-REGULATOR-ELEC-01-154-16-p/12-3090a.htm

The problem im having is that the battery shows 12.1v while running last i checked and every time i start the motor it shows a little less, yet i have 16v coming out of the reg/rec itself. Do i just have the wrong part? I dont understand how i can have voltage coming out of the reg/rec but when its connected to the battery its as if there isnt any voltage at all. ive been fighting this thing for a while now. Any help is greatly appreciated.
 

TwoFish

Petty Officer 1st Class
Joined
Aug 7, 2010
Messages
373
Re: Charging problems on a '91 120hp Force

Welcome to Iboats orignagah,

Sounds to me like the “red” charging wire on the regulator is not connected to the positive battery terminal for some reason (incorrect wiring, broken wire or corrosion). Could also be a bad ground as well. This will burn out your regulator as it has nowhere to send the charge. NEVER DISCONNECT THE BATTERY WHIST THE MOTOR IS RUNNING.

The easiest way to test this that I know is to use a multi-meter set to ohms or continuity. You need to test that the wires connect to the battery. Disconnect the boat battery to prevent frying the multi-meter if you ground the probe by mistake.

The red wire usually goes from the regulator to the positive supply side of the starter solenoid where it connects to the main positive cable from the battery. If you place one probe of the meter on the positive terminal of the main battery cable, at the battery end, and the other probe on the connector the red wire on the engine loom that the connector red wire from the regulator goes into you should get a closed circuit (0.000 ohms). If you get “0.L” you have an open circuit. If you get a above 0.000 ohms you have resistance in the circuit (corrosion ,bad connection). If someone has been working on the started solenoid it is easy to connect the red wire from the regulator to the wrong stud on the solenoid when putting it back together.

You can test the grounding on the regulator the same way. One probe on the main battery cable connector at the negative battery end and the other end on the loom connector at the regulator end (BLACK wire).

On these test you need to test the wires on the engine loom not the wires on the regulator.

The regulator should restrict the voltage to about 14.5 volts. 16 volts sounds too high. Not sure what they read if run on an open circuit. 16 volts is normal for a rectifier. The part number you supplied shows it as a regulator as it doesn't regulate the volts. Either way it should be charging your battery.

Hope this makes sense. If not let me know if it is difficult to follow and I try to explain it better with some photos.

Good luck.
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
Re: Charging problems on a '91 120hp Force

One thing that was not mentioned is the ckt bkr between the starter solenoid and the rectifier. Check the ckt breaker it might need to be reset. To make sure it is reset, check voltage across the rectifier (red and black wires) and you should read battery voltage with the engine off. If not the ckt breaker is tripped.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
Re: Charging problems on a '91 120hp Force

mercury reg/rec #5279

Thats not a Merc part number. That is a CDI part.

1991 was a bad year for Force ignitions. They were switching ignition systems, and used a number of configurations.

Does your motor use the blue cd modules and coils?

Or does it use a switchbox ignition?

Do you have the serial number available?
That regulator should work if your serial number is between E006551 and E369299


The cd module ignition used a rectifier.

The switchbox ignition used 3 different rectifier/regulators, depending on your serial number.
Merc charges about $175 for these.

http://www.crowleymarine.com/mercury-outboard/parts/1470_40.cfm


THese things were $58 just a few years ago.


If all else fails in finding the wiring problem , you can extend the red wire and connect it directly to the pos terminal on the battery.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
Re: Charging problems on a '91 120hp Force

Welcome to Iboats orignagah,

Sounds to me like the “red” charging wire on the regulator is not connected to the positive battery terminal for some reason (incorrect wiring, broken wire or corrosion). Could also be a bad ground as well. This will burn out your regulator as it has nowhere to send the charge. NEVER DISCONNECT THE BATTERY WHIST THE MOTOR IS RUNNING.

The easiest way to test this that I know is to use a multi-meter set to ohms or continuity. You need to test that the wires connect to the battery. Disconnect the boat battery to prevent frying the multi-meter if you ground the probe by mistake.

The red wire usually goes from the regulator to the positive supply side of the starter solenoid where it connects to the main positive cable from the battery. If you place one probe of the meter on the positive terminal of the main battery cable, at the battery end, and the other probe on the connector the red wire on the engine loom that the connector red wire from the regulator goes into you should get a closed circuit (0.000 ohms). If you get “0.L” you have an open circuit. If you get a above 0.000 ohms you have resistance in the circuit (corrosion ,bad connection). If someone has been working on the started solenoid it is easy to connect the red wire from the regulator to the wrong stud on the solenoid when putting it back together.

You can test the grounding on the regulator the same way. One probe on the main battery cable connector at the negative battery end and the other end on the loom connector at the regulator end (BLACK wire).

On these test you need to test the wires on the engine loom not the wires on the regulator.

The regulator should restrict the voltage to about 14.5 volts. 16 volts sounds too high. Not sure what they read if run on an open circuit. 16 volts is normal for a rectifier. The part number you supplied shows it as a regulator as it doesn't regulate the volts. Either way it should be charging your battery.

Hope this makes sense. If not let me know if it is difficult to follow and I try to explain it better with some photos.

Good luck.


If someone has been working on the started solenoid it is easy to connect the red wire from the regulator to the wrong stud on the solenoid when putting it back together.


This is where I would start looking for a wiring error.
 

orignagah

Recruit
Joined
May 30, 2012
Messages
4
Re: Charging problems on a '91 120hp Force

thanks everyone for your responses!!

TwoFish- i will do the ohm test to the battery as u mentioned. i did the same test but only on the motor itself, didnt go all the way to the battery.

Jiggz- Im not sure that there is a breaker but there's a fuse that is still good. i will double check for a breaker though.

Rosco- I think the 194-5279 is the one made by cdi. The 5279 i think is the pro marine number for the muercury one. the serial # on this motor is 0E013397. It does use a switch box with coils, not the cd modules. I did run a jumper wire straight to the battery from the reg/rec. As soon as the wire hits the battery terminal the voltage drops down to 12.something.

I will be working on the motor again as soon as i get a chance and will post any updates i have. Any more information you all might have is greatly appreciated. Thanks again for your responses!!!
 

TwoFish

Petty Officer 1st Class
Joined
Aug 7, 2010
Messages
373
Re: Charging problems on a '91 120hp Force

The charge should drop down with a load on it at idle speeds. At Idle speeds you will only get around 12.5 volts. The stator will not generate enough power at idle speeds to supply much more than 12 -13 volts. At engine speeds of 2000rpm and over the voltage should increase to 14.5 volts. If the regulator is working correctly the voltage will not go higher than about 14.5 volts.

The charging circuit is fairly simple. The stator supplies alternating current (AC) by moving magnets past coils of wire. The AC current is then converted to Direct Current (DC) by either a rectifier or a regulator.

A rectifier converts AC to DC but does not restrict the voltage output and can reach 16 volts or more.

A regulator is just a rectifier that has another circuit in it that restricts the voltage to about 14.5 volts. The extra volts are dissipated by the regulator as heat.

The two yellow wires leading into the regulator are the AC wires from the stator. The BLACK wire is the negative DC out. The RED wire is DC positive out. The GREY wire is the signal wire for the tacho. It is AC but has the signal smoothed out to make it easier for the tacho to read. It is possible to use the signal from either of the yellow stator wires for the tacho.

As mentioned before the regulator should always be connected to the battery whilst the motor is running. Otherwise the power from the stator has nowhere to go and fries the regulator.

As far as I can tell from the wiring diagram if the fuse is blown nothing will work. No power to the motor circuit so it will not crank or start.
 
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