24ssv Intermittent Engine Loss of power and electrical issues

[Ryan-2010supra24ssv]

Hey guys, im new to this forum and a new boat owner. I just bought a 2010 Supra 24-foot SSV and I love it so far, just trying to work out some of the kinks.

Originally the owner was having what he thought was some radio problems where the speakers would shut off randomly and I figured it was a grounding issue. the first couple of times that I took the boat out I also noticed that the MB quart remotes for the stereo would go blank, but the back light was on and the volume functioned. Also the supra vision screen showed random letters where you normally see the AUX OR VOLUME on top/left of main screen. I was starting to think my stereo unit was going out or maybe the connection between the stereo and the supra vision was bad...
I wanted to upgrade the speakers anyway so I had all the speakers replaced and I was able to tighten some ground wires which fix the shutting off issues but was still having the blank remotes intermittent, mostly blank.
The other night when I was parking it I had most of the lights on and as I was coming in I tripped a breaker in the system which shut off everything except my engine and main controls. I thought maybe the lights and stereo and everything else overloaded it? After I parked, I left it tripped, and turned the main battery switch off.
Last night when I was out, I arrived at the boat and turned everything on and now the radio streams seem to be working fine after it set for a few days with the main breaker tripped. Everything started off great but after about five minutes in Cruise I slowly started losing power, noticeable by "the feel" and the speeds gradually slowing down even though the throttle was hammer down. We started off around 33 miles per hour and after about 5 minutes we're down to about 10 miles per hour. I also noticed that my depth finder gauge was reading wrong. The radio screens were working great😜.
So, I stopped and it idled great, no issues at low speed. I turned it off and started back up, and had my power back, mostly at cruise, but a few minutes later I had the same problem, and gradually lost power. I shut it down again this time I turned off the batteries and trip the main breaker. Started it back up with no problems and now it seem to be working much better, but now the miles per hour gauge was off. I had to have been running at least 25 miles per hour at about 3000 RPMs but it showed me going 10 miles per hour on the gauge.

Last thing I did in frustration was shut everything down and I went under the dash and started unplugging and plugging back in my wires to see if there was any shorts or oxidized lines that could be causing these intermittent issues. When I started it up it seem to be working better but it was dark by now and was tired of messing with it.

I don't think it's fixed and was hoping that someone on this thread could help me by guiding me in the right direction to a possible solution or problem.

Thanks for your patience in reading this and your time. Ryan

[Turbinesurgeon]

Well I’d start with cleaning all the battery cables, ground cables and don’t forget the cables in the perko switch. Also what is the health of the batteries and what voltage are you showing from the alternator? I’ve had a voltage regulator fail and throw 16 volts at the system. Slowly cooked my electronics.

[Ryan-2010supra24ssv]

Well I’d start with cleaning all the battery cables, ground cables and don’t forget the cables in the perko switch. Also what is the health of the batteries and what voltage are you showing from the alternator? I’ve had a voltage regulator fail and throw 16 volts at the system. Slowly cooked my electronics.

Thanks for your response. I will go out to check those items the next time I'm out, but everything in the battery compartment looks great. I did tighten down the terminals but never took them off and cleaned them.

I took it out the other day after my original post and the boat ran great, but the only issue I was having was with the ballasts. The right ballast switch and the center ballast switch were crossed. meaning when I was trying to fill up the right rear locker ballast, it filled up the center ballast and vise a versa. I haven't messed with the ballast enough to know whether they were correctly working when I bought it, so who knows it could have been crossed before... I did suspect some issues originally but I assumed it was a pump issue. And when I had the problem the other day, I immediately thought that I would just need to flip the wires at the switches, but now I'm starting to think maybe all of this is connected. Do you think that my other electrical issue could make these switches flipped?

Last night I took it out again and at first everything ran good, but after sitting in a cove for a while with the engine off and radio on, the radio screen normally displaying AUX, started having weird characters start to show up. GREAT

VIDEO]https://photos.app.goo.gl/enWqhH7Gjt6RudoJ8[/VIDEO]

So I immediately started playing with the wires again under the ateering wheel and got it to temporarily straighten up but never fully fixed while we were sitting there. After I started up the boat and started driving, it seemed to start working properly again. Here's the really weird part, when I got back to the marina, my center ballast was half full of water and I know for sure the switch was not on...

Any info would be great but I'll check back when I have cleaned up the batteries and check the voltage from the alternator...

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Thanks Again

[Turbinesurgeon]

I’m not sure about 2010 but my 2006 had Orbit sprinkler valves for the Gravity Games system. They’re totally junk. One of the first things I did with my boat when I bought it is removing those and re-doing the whole system. Bags filling up on their own is a sure sign one of the valves failed. You can grind off the scupper on the bottom of the boat so it won’t auto fill or you can install a motorized ball valve in place of the sprinkler valve. I used the motorized ball valve and installed independent pumps on the rear bags. I did a more in depth post on this subject on the Moomba Modification forum.

After your done cleaning all your battery cables and grounds you should take note of your battery voltage and voltage while it’s running.


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