What would cause my Rectifier to short out? 1996 90 SLE ocean runner

My battery hasn't been charging lately and I started digging around on the forums and went out and removed the cover and wiggled the wires while inspecting them and the red wire immediately started smoking and later completely separated from the rectifier.

So I am guessing (hoping) that the short was in the regulator, but after reading around more, I understand that it could be caused by a 'hard short to ground'

I'm not sure what that means exactly, but I don't see anything visually that looks problematic. No wires look bare or heat damaged as far as I can tell.

I installed a perko switch for my two batteries after I put the new rectifier in and I'm hoping that will keep anything crazy from happening while the boat is unattended. At least it won't burn down my house or something as long as the switch is off...

So what would cause a "hard short to ground"? The old battery hardware has definitely been too loose to start the motor in the past, but not at the moment of (noticed) failure, they were plier tight on the last 2 hours of operation since I last disconnected the battery and reconnected after a charge.

I just don't want to ruin this really expensive part ($244 +tax!). Please help if you can.

Thanks,

Cliff

Re: What would cause my Rectifier to short out? 1996 90 SLE ocean runner

Blown diodes in the rectifier can short to ground. Running the motor with no battery or loose battery cables can cause the rectifier to blow.

Re: What would cause my Rectifier to short out? 1996 90 SLE ocean runner

Add to the above:
Loss of cooling might create an air bubble on top of the cylinder and the rectifier gets overheated and melts internally.
Check you impeller and thermostats.
Another thing that might cause break down is recharging a flat battery or too big battery banks. They are not designed for max output over a long time.
I hope your Perko switch has the safe function that allows switching batteries when running engine. Switching batteries when running normally means you break the circuit before opening the other which will kill the rectifier the same way as running with unconnected battery.

Re: What would cause my Rectifier to short out? 1996 90 SLE ocean runner

The picture of the ign system for that motor shows a water coooled voltage regulator. Is that what you have? It will be under a plastic cover behind the flywheel.
If it is blown, there are aftermarket replacements for less that the price you quoted.

I recommend you inspect the motor harness for melted wires. The red wire should go directly to the starter solenoid battery post, so it will be easy to inspect. Check out the grey tach wire and purple wire. If you disconnect both of those at the ign key they should not show any connection to ground.

Re: What would cause my Rectifier to short out? 1996 90 SLE ocean runner

Thanks everyone for your input. To be clear, the new part is in and I tested it and it seemingly worked. I inspected the regulator and it wasn't hot to the touch after a few minutes...That's when I wondered what else could be wrong.

There's one accessory fuse block that's getting kind of nasty looking, could that cause the hard short? I thought no because the fuses would blow if anything. It would take a screwdriver or something across those terminals to do something crazy, right?

@bhile- The batteries shouldn't be bad, one is a year old and one is two years old. (looks like I'm buying a voltage meter today...)
HOWEVER the wingnuts have been loose enough times for me to think that's why I've got this problem to begin with. I re-secured everything down with new terminals and new hardware, two nuts on each post.

@Haffiman- The water pump seems to be okay, telltale is pissing and the alarm isn't going off....I'll change that impeller out soon, I've owned the boat for a year and there's no telling when it was last replaced (previous owner got all of the service paperwork wet...)

Would the thermostats be tied in to that heat alarm system? I'll figure out where those are and make sure they're alright.

I read that perko has a 'make before break' feature that makes the next connection before it shuts down the old one (That's as I understand it)

@Chris- Too late, there was only one in town and I'm going to the keys tomorrow! I reattached it just like I found it, there was a large battery looking wire on there with it, so I figured that was the hot spot.


Thank you for all of the replies!

Re: What would cause my Rectifier to short out? 1996 90 SLE ocean runner

Do yourself a favor and replace the wingnuts with stainless steel nylon lock nuts, or regular SS nuts with lockwashers. When the wingnuts get loose they can cause the rectifiers or VRs to blow their diodes.