Bad Rectifier?

[auchandler1]

I was reading up on some threads about how to find the problem when your tachometer doesn't work. Basically they seem like all the same..could be the tach...could be a wire...could be a blown fuse? I saw to check the rectifier on the outboard and read about rectifiers. I notice that this was the device that charges the batteries as well. Don't ask why I didn't know that but I at least knew there was something that charged it. Anyways, I then notice that my batteries do not really charge or I thought so I went ahead to check to see if my rectifier is good. I used a digital multimeter with this project. I disconnected positive and negative to both my batteries and then following the instructions has the multimeter in the V(guess as in volts reading) and hooking up black to ground and red to the wire that was red and showed some voltage but when I touch the other two I believe it said AC on both they showed nothing... My guess is its a bad rectifier since it doesn't seem the power is flowing through.

What is your thoughts?

Thanks

 

[riptorn]

Re: Bad Rectifier?

You set the DVM to diode setting to check the rectifier. There are a few ways to check if your battery is charging. Disconnect your battery while the motor is running for about 5 seconds and if still running then it is giving some charge. Another way is to take a battery volt reading before and after you run the motor. Outboards charging systems don't give a high amp charge. Just enough to keep the battery topped up without accessories running. As far as I know. Don't know about brand new O/B.

 

[SweeperForce]

Re: Bad Rectifier?

Start with the battery(s) disconnected. Take a reading from your muiltimeter. Set it to VDC, red lead to positive terminal and black lead to the negitive terminal. It should read between 11.5 and 13 volts. Never run your motor without a battery, this will for sure fry your rectifier. Make sure all you connections are tight and corrision free.
There should be two green wires coming out from under your flywheel. Theres are AC wires.

Now these wires should be connected to the yellow wires coming out of the rectifier. The tach wire also connects to one of the yellow wire. (either one) Some rectifiers ground trough the case. Remove it and sand the back of rectifier with fine grit sandpaper. Also sand the area of the motor where the rectifier attaches. Make sure the mounting screws are not corrided. The red wire goes to the circuit breaker(make sure the button is push in). From the circuit breaker, that wire goes to your battery from recharging.
Now peel back a little insulation on the green wires. Set you meter to AC. Start the motor, put one lead on each wire. At idle you should get around 25 volts AC. If so, your stator is good. Keep the motor running, check the battery(s) again. Set your meter to volts DC. It should read 13.5 to 14.4 volts DC. If so, then your rectifier is charging your battery(s). Now this leaves the two yellow wires. Make sure the connection between the yellow and green are good and solid. Make sure the tach wire has no cuts or breaks inside the wire casing. Use you meter to check the continuity of that wire. It is cheaper to replace the rectifier than the tach. I hope this helps.

Tom

 

[SweeperForce]

Re: Bad Rectifier?

You set the DVM to diode setting to check the rectifier. There are a few ways to check if your battery is charging. Disconnect your battery while the motor is running for about 5 seconds and if still running then it is giving some charge. Another way is to take a battery volt reading before and after you run the motor. Outboards charging systems don't give a high amp charge. Just enough to keep the battery topped up without accessories running. As far as I know. Don't know about brand new O/B.

I beg to differ, NEVER run an outboard without a battery, you'll fry the rectifer.

Tom

 

[riptorn]

Re: Bad Rectifier?

I agree SweeperForce good post but 5 second won't make a differents. A dead battery would do more damage taking a charge (especially one's with shorted plates). Rectifiers are pretty cheap to buy unless you want the heavy duty ones with the heat sinks.
Good luck auchandler1

 

[auchandler1]

Re: Bad Rectifier?

Ok guys come to find out it was the rectifier. I went to radioshack and bought at $3.00 25amp rectifier from the store and put it on. Using different wire connectors I stripped the old wire and crimped the new one. After I got the rectifier hooked up and connected the batteries up I started the engine and the gauge started working and my batteries were getting charged.

Thanks for the help guys

 

[SweeperForce]

Re: Bad Rectifier?

I went that route also. Check your voltage at the batttery, I was getting 16 volts and higher when I revved. Becareful that you don't cook your batteries. If that rectifier works for you, great, but I needed a rectifer/voltage regulator. I always get 14.4 volts. To be completely honest with you I am using a snowmobile rectifer/voltage regulator. Only cost me $45.

Tom

 

[riptorn]

Re: Bad Rectifier?

Good going auchandler1.

 

[riptorn]

Re: Bad Rectifier?

I went that route also. Check your voltage at the batttery, I was getting 16 volts and higher when I revved. Becareful that you don't cook your batteries. If that rectifier works for you, great, but I needed a rectifer/voltage regulator. I always get 14.4 volts. To be completely honest with you I am using a snowmobile rectifer/voltage regulator. Only cost me $45.

I don't think you would cook your battery. More like your wireing at the stator/rectifier. A 12 volt battery is 2.2 volts x 6 plus.