Nagging Issue - Electrical power goes dead

[chautauquasun]

Hello...it's been a long time since I have been on here. Have been enjoying the supra and working way too much. This board has always helped me trouble shoot certain issues and I am sure you can help me with this one. I own a 1984 Supra Rider, 351w that I restored a few years back. It has been running fine but I have a nagging issue that I can seem to fix. At times the boat just goes completely dead, meaning I have no power when I turn on the key. Gauges don't respond and I have no electrical power. This has happened when the boat is on the lake running and has happened when sitting on the trailer. I thought maybe I had a loose wire somewhere due to rough water but ruled it out when it happened on the trailer. It is funny. It will be running fine. I turn it off and then try to turn it back on and it is dead. If I wait a little bit it seems to correct it self. Recently I started to remove the wire from the ignition switch to the fuse box then plug it back in and it works every time...I then have power...almost like it resets itself. Is this a faulty ignition switch or could it be the safety switch that won't allow you to start the boat in gear. Keep in mind...it still does this even when it is in neutral. I replaced the old battery cables two years ago thinking they were shorting but that didn't correct it. Again, I am able to keep the boat running....it is just annoying when out skiing and you are ready to start it up and take off and it is dead.

Has anyone else experienced this issue? Any thoughts? My next step is to replace the ignition switch but not really sure if that is the issue.

Great to be back. Thank you for any help you can give me.

Dan

[flipz96]

I've had this happen to me before. For me, it was a corrosion on the battery terminals. I replaced mine, but I could have sanded them done to the metal. Good luck!

[chautauquasun]

Thank you or response. But I don't think that is it. I replaced the terminals when I replaced the cables two years ago. There is no corrosion on the terminals. It completely goes dead...no power to the gauges. Has anyone else experienced this?

[SquamInboards]

I have had it happen under certain conditions, and it has always been the main breaker on the engine. I've seen it happen on more than one boat, same thing. In one case I just tightened/cleaned the connections on the breaker. I think in the other case I replaced the breaker. It would make a very unsatisfying click when I pushed it to reset. But any time there was no power to the dash, it was always solved by resetting - or just the act of messing with - that main breaker.

[chautauquasun]

Yeah, I have often thought that was the issue, but many times the button didn't need to be reset. The last few times, I have not bothered pressing the main breaker I simply unplugged the ignition power from the fuse box and it worked. Could this have anything to do with the kill switch that wont allow you to start the boat in gear?

[flipz96]

Something is causing a break in current. Either a bad breaker, pinch in a wire, or bad connection. I just rewired my helm and I noticed some of the original wire looking corroded or even burnt looking. I would try replacing the breaker and some of the wires. Maybe you moving the ignition wire causes the pinched wire to touch and allows you to start. Just throwing out ideas. Good luck!

[UKandH]

Without any further diagnostic checks its difficult to locate the peoblem. If the boat wont run, you have no ignition feed to the instruments either, it is sounding like an ignition feed fault from the switch to the rest of the boat. I have seen this on my TS6 so i rewired that starter and ignition switch as a matter of priority.

Check the connections at the back of the switch, also check the inter connects from the main boat harness to the instrument area as the main power goes through that connector from the motor mounted breakers. Pull the connectors apart and look for brown stains on the plastic which indicate high temperature problems caused my high resistance connections in the terminals. Its going to be something along those lines.

Andy

[SquamInboards]

Without any further diagnostic checks its difficult to locate the peoblem. If the boat wont run, you have no ignition feed to the instruments either, it is sounding like an ignition feed fault from the switch to the rest of the boat. I have seen this on my TS6 so i rewired that starter and ignition switch as a matter of priority.

Check the connections at the back of the switch, also check the inter connects from the main boat harness to the instrument area as the main power goes through that connector from the motor mounted breakers. Pull the connectors apart and look for brown stains on the plastic which indicate high temperature problems caused my high resistance connections in the terminals. Its going to be something along those lines.

Andy

That's the right track, if it's unrelated to the main breaker... I've replaced the ignition breaker on my boat as well. The connections back there behind the dash are not the best. Those spade connectors just aren't the best thing after 20+ years in a moist environment.

It's not related to the neutral safety switch because that doesn't cut off power to the whole dash.

[chris young]

How dead? Can you turn on the blower, lights, bilge pump? If not, it has nothing to do with the ignition switch. If all that works, then for sure it could be the ignition switch or just a loose connection on the switch as mentioned above. You can use my diagram to work on your boat, I based it on my boat, which is also an 84 Rider.
https://forum.supraboats.com/showthr...wiring+diagram

[SquamInboards]

At times the boat just goes completely dead, meaning I have no power when I turn on the key. Gauges don't respond and I have no electrical power.

Sounds like it's everything, no power to accessories or anything...