89 Johnson v4 90 hp troubleshoot

She almost burned down today!

Everything ran perfect all day as usual, with quite a few short runs from spot to spot.

At the end of my fishing day I headed towards the launch and it was occupied so I made a lap around the lake to kill time.

3/4 to wide open for about five minutes. Get close to the launch and get a whiff of burning electrical! Look back and the motor has white smoke pouring out the cowling.

I shut it down quick, grabbed the fire extinguisher, and waited for a second to see if it quit. Nope! Opened the hood and it only took a second for a small flame to ignite.

I doused it good with the fire extinguisher and it wouldn’t stop. I then disconnected the power from the battery, and it stopped the short, which was had lit the plastic back on fire. I hit it again with the fire extinguisher and it snuffed it out.

Oh yeah, this is all happening in about three feet of water and 10 mph wind towards the shore btw
What a poop show!

My questions are:

What is this part called?
What caused this?
Can I replace the part and be ok or do I have bigger problems?
Do you guys have a way to cut power that is more convenient than opening the back hatch and unscrewing the wires from the battery?

I feel like I had a close call today and this has got me thinking safety.
I will admit I wasn’t wearing a life jacket and this little thing could have gotten serious in a hurry.
Going forward I will be wearing one 100 percent of the time.

Probably the voltage regulator. Does it connect to the stator?

This is a common symptom of a faulty voltage regulator. Have you noticed any odd behavior by the tachometer?

Get a main power shutoff switch. Here’s a cheap one.

Battery Switch, 12V 24V 48V Battery Disconnect Master Cutoff Switch for Marine Boat RV ATV UTV Vehicles, Waterproof Heavy Duty Battery Isolator Switch (On/Off) https://www.amazon.com/dp/B07HT19T5V/ref=cm_sw_r_cp_api_glt_fabc_ZBTTD1RKE96P75E3CS8R?_encoding=UTF8&psc=1

Voltage regulator, the burnt spot is where the diode sits.
This type of failure is directly tied to a battery problem or dead short.
Battery, age?? make??

Thanks Matt that looks like it will work.

Iowaboy it is a fleet farm resolute deep cycle. February of 19′

Yes the tach has been acting up Matt

Jake, is the battery a maintenance free type??
I hate to admit it but I am not familiar with the resolute series.

No it’s not. I added some water at the beginning of the season. Looks like it leaked a very small amount because it’s nearly full.
The positive wire was very hot when this happened and I only disconnected the negative at the time.
Now that I look at the positive wires they look pretty charred up at the battery post.

Iowaboy1 wrote:

This type of failure is directly tied to a battery problem or dead short.
Battery, age??

It’s probably no coincidence that I had a melted connector between my voltage regulator and stator and I had a bad coil and power pack this year. I also had a 6 year old starting battery that finally died.

My engine is a 2002 150 Johnson.

If you were using that old battery at the beginning of the year that is what started this mess.
the melted connector was your first clue to the amount of heat generated in an overcharge/overvolt situation.
when the regulator, ( and yours is water cooled as the bottom of it sits in the water jacket in the vee ) gets too hot the diode goes out, and from there its sh!t show that costs big bucks as you found out.
air cooled rectifier/regulators burn out much quicker!!

I will bet the stator is toast as well.

I have a few threads here on IDO about this problem happening.
If I can be of further help PM me and I walk you through the repairs.