electrical problem!

[mangyna]

I have a 91 johnson which shorted out the voltage regulator and put a used one in (half the price of new) and went to start the motor and it acted like the batteries were dead and the grounding wire at the bottom of the motor pan got red hot, needless to say it did not start? Any guesses would be appreciated! Thanks

 

[fireman57]

Re: electrical problem!

Sounds like you have a bad connection somewhere for the wires to get hot. How big an engine are we talking about? If you can put it on muffs or in a barrel you can jump from the battery to the starter after disconnecting the red cannon plug in your wiring harness. If it starts then you know the problem is before the starter. Check for bad solenoid, loose or dirty connection, or a burned wire. When you do this you will not be able to turn off the engine with the key so you will have to choke it to kill it. Do not rev it in neutral if it starts.

 

[Texasmark]

Re: electrical problem!

Not much to go on, but the comment about drained batteries and red hot ground wire suggest that you have the + voltage wired to ground.

Now how did you do that?

Either you got your wiring crossed, or your used rectifier has 1 or more shorted diodes going from the + terminal to ground inside the rectifier.

The rectifier has 4 terminals: 2 AC inputs usually the same color wires which originate under the flywheel, a ground, usually obvious black wire tied to a rectifier mounting screw, and the + output that goes to your regulator if you have one; if not to your wiring harness and then the battery + terminal.
----------------------
Disconnect your battery and take an ohm meter and put it on 2k ohms scale and measure in both directions from the battery + to - wires (like take a reading and reverse your leads and take another) in the harness going to the battery with it (the battery) disconnected from the harness. In one direction you should read a low value of resistance; in the other an open circuit. If you don't get the open circuit, rather another low reading, I'd suspect shorted diodes in your "new" rectifier. If it's not that you wired up something that you shouldn't have and you have + voltage going to ground.

Mark

 

[jtexas]

Re: electrical problem!

When you say "acted like batteries were dead" - what exactly happened when you turned the key...did the starter spin? Did the solenoid click?

The red-hot grounding wire - I'm curious about what wire that is...what's at either end of it?

Did it heat up when you connected it, or only when you engaged the starter?

Is that a voltage regulator separate from the rectifier, a rectifier/regulator, or just a rectifier?

Engine HP or model number would help.

 

[mangyna]

Re: electrical problem!

Hey guys thanks for all the info it is very useful! Sorry about the not posting HP and other info! It is a 91 Johnson Faststrike 150 60deg V6. The grounding wire that got red hot grounds the motor to to the motor transom bracket. Not even sure it is a ground wire! It is more like a small cable as opposed to a copper ground wire! i assume thats what it is? Anyhow i went through most of the wiring and all looked good, it would heat up when i crancked over the motor, and yes it would turn over but acted like an engine being turned over with a weak battery slowwwww cranking, i run two batteries with the engine, also the motor is bolted to an aluminum boat. what caused the whole mess was when i started the motor at home on the hose and left the batteries on and walked away for a minute and came back and smoke was rolling out of the cowling, so hence the used voltage regulator, the existing one was melting not sure why?

 

[jtexas]

Re: electrical problem!

Why two batteries?

What does "left the batteries on" mean? Was the engine running?

Also please describe how your batteries are hooked up.

Is that the stock rectifier/regulator or have you modified the system?

 

[mangyna]

Re: electrical problem!

Hey thanks for the feedback jtexas! the boat came with 2 batteries when i bought it!They (batteries) are behind a switchwhich you can kill all electrical currant to the boat and motor. the batteries are connected via cables. and i did start the motor one time with the new (used) regulator but after that the rest is history.The voltage regulator was stockthat came with the motor.and the replacement was a direct numbers match replacement.

 

[jtexas]

Re: electrical problem!

When you said "i started the motor at home on the hose and left the batteries on", what did that mean? Do you normally turn the battery switch off with the engine running?

What settings are on the switch (e.g. "Off, Both, 1, 2)?

What setting do you use for cranking the engine?

How old are the batteries, are they fully charged?

Your "voltage regulator" is a rectifier and regulater built in to the same package.

 

[Seasport]

Re: electrical problem!

Sounds to me like the starter motor current is trying to flow through that thin ground wire rather than the heavy duty ground cable which goes from the powerhead to the battery. This would make that thin wire smoke and you wouldn't get much action out of your starter motor either.

Check out the main ground cable that should go from the -ve terminal of the battery to the powerhead. Make sure it's securely connected at each end.