A hot rectifier

[ddbyrd3]

On my 1981 140 Johnson, I noticed that the volt gauge was only pointing at 12.5 volts regardless of RPM, but I have no battery problems even after running all day with the radio on, skiing, etc.<br /><br />The tach is working fine, but I felt the rectifier and it was real warm, maybe even hot.<br /><br />Is this normal, I replaced the stator last season (doesnt mean its good) <br /><br />I was just curious.

 

[angus63]

Re: A hot rectifier

First step is to remove and clean all of the wire connections (especially the grounds) associated with the charging system (battery as well). If charging doesn't improve and rectifier is still hot, get the factory manual and follow the troubleshooting of the charging system components. Manual can be had at theoutboardwizard.com website.<br />Good luck

 

[ddbyrd3]

Re: A hot rectifier

Definatly, when I get home today, I will run the boat under load and using a volt meter verify the voltage reading at the gage to make sure I dont have a faulty gage. <br /><br />Is it usual for the rectifier to run warm/hot though, or should be be cool to the touch????

 

[angus63]

Re: A hot rectifier

Warm but not too hot to touch. really depends on batt, load, run time....

 

[ddbyrd3]

Re: A hot rectifier

Ok,,, thats about what mine was, it wasnt to hot to hold, but felt warmer than I would have expected. <br /><br />I will run it and use a volt meter on the volt gage to assure it is charging correctly... Hopefully its just a faulty gage..<br /><br />Thank for the input..

 

[fishforsanity]

Re: A hot rectifier

I have the exact same problem on a johnson 88 SPL. Has anyone detirmined that a hot rectifier is bad if it is working? Is there possibly another problem other than the ground. I have checked everything twice. Is there maybe another bug that anyone has found. In the wiring maybe?<br /><br />thanks<br /><br />SkipperArch

 

[Silvertip]

Re: A hot rectifier

To check the rectifier, disconnect the two wires going into it (usually yellow), and the red wire coming out of it. Using an ohm meter, touch one probe to red wire and the other probe to one of the input wires (yellow). Note the reading. Then reverse the probes and again note the reading. Repeat the test for the other input wire. In one direction the resistance should be high and when the probes are reversed the reading should be low (near zero). If both readings on either wire are the same (high or low) the rectifier is bad. Any electrical device that carries a significant amount of current will create heat. Warm to the touch is not an indication of a bad rectifier. AC Voltage into it and no DC voltage out of it is a sign of a bad rectifier.

 

[fishforsanity]

Re: A hot rectifier

Thank you Upinsmoke,<br />I am almost willing to try it for a day at the risk of it costing me 300.00 or more in parts. I checked the system both the rectifier and the stator and they check out. The system is putting out from 13.5-14volts at 1100 rpm. The only thing is that it gets gradually hotter until you could touch it but not hold your fingers on it. After running it for 5-6 minutes it is too hot to keep your hands on it and it has not been tested at high RPMs. Not sure what hot is but I want to say at 1100 rpms it is in the 130-150 degree range. On the good news it is charging 14 volts and back to 13. something on a single battery. Do I dare use it like it is? I have two other double battery banks of size 27; agm batteries that make it hotter quicker. Do you think that it is ok to charge one of the parallel wired pair to recharge the deep cycle set up in a day? <br /><br />SkipperArch

 

[wilde1j]

Re: A hot rectifier

To check the rectifier, simply measure across the battery terminals with a DVM with the motor running. You should get > 13.5 vdc. If you get 12.7 vdc, or less, you can be sure charging is not happening. Logical failure choices are wiring, stator or regulator/rectifier. Do not disconnect any wires with the motor running or try to run the motor without all properly connected, unless you don't mind replacing expensive parts.

 

[Seasport]

Re: A hot rectifier

Normally the rectifier should be able to handle all of the current capable of being generated by the alternator (stator windings). So shouldn't matter about the battery load. The alternator can only supply so much current. However, I do notice that you replaced the stator. Just a thought - are you sure this was rated at the same current spec as the original? Just maybe you installed a stator with a higher current output capability and the rectifier is not rated to carry this much current.

 

[xltier]

Re: A hot rectifier

rectifiers run pretty hot.thats how they work.thats why their made the way they are.

 

[fishforsanity]

Re: A hot rectifier

I got the parts from a dealer and they said that they were the right ones. Hot varies from not being to hold your hand on it for more than 4-5 seconds, to a little cooler. Is there any temperature that I can look for? As for the stator output I have about 14.5 volts at 1100 rpm max. Often I have less. The voltage starts at around 12.28 and slowly climbs as the rectifier gets hotter. The original stator on this boat looked like a disc with a hole in it and the one that they sold me looked like a circle of bumps. The box reads 583340 The box says 6 amps rectifier says 27-CID-Ba (6 amp). If there is a short I have not found it yet. I also have a sierra one that has a slight different OHM reading and it seems to get hot quicker. So how hot is too hot??<br /><br />Thanks xltier <br />Seasport WildeOne & Upinsmoke <br /> <br />SkipperArch

 

[Seasport]

Re: A hot rectifier

By the sound of it you're probably fine. As xltier says, rectifiers do get hot. You could try measuring the current draw with an ammeter. I'd be surprised if it was more than 6A DC.

 

[fishforsanity]

Re: A hot rectifier

Guess I will soon find out; thanks everyone!