Engine stalls out while driving

Hopefully somebody has experienced this and can help solve the issued.
While I was pulling the kids knee boarding, I adjusted the trim, and when I did the engine stalled but started right back up on its own and the perfect pass shut off and came back on. It did this again when we were surfing, it wasn’t the trim tab I adjusted I went to empty some water out of a ballast bag. As soon as the pump turned on it did it again. I always have the battery switched to #1 while I’m driving. I feel like maybe the house battery might be dying or is dead and whenever I put draw on the house battery by turning on a pump or moving the trim tab could it be pulling too much voltage from the engine battery and shutting the system down? Or is the voltage sensitive relay not working properly? Any thoughts on where I should start to diagnose an issue like this would be appreciated.

Sounds like a dead battery. I'd get it tested. If both of your batts are identical no need to only run on the 1, leave it combined the full time running or not. The pumps pull a lot of amps especially if you have 6 running at once. That being said don't combine a dead battery with a good one.

Depending on the year and model you have there were a few alternator issues as well that might need to be checked out if the battery charges and checks good.

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Originally Posted by RUGER761

Sounds like a dead battery. I'd get it tested. If both of your batts are identical no need to only run on the 1, leave it combined the full time running or not. The pumps pull a lot of amps especially if you have 6 running at once. That being said don't combine a dead battery with a good one.

Depending on the year and model you have there were a few alternator issues as well that might need to be checked out if the battery charges and checks good.

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I have a 2006 Mobius LSV. You run on selector 1&2 full time? I assumed the relay would automatically charge the house battery when the starting battery reaches peak voltage?

Only if the two batts match can you run them combined the full time, if not identical (one starting one deep cycle) need to separate while the engine is not running, combined when the engine is running so both charge. Does your LSV have a charging relay or charging diode wired in? Most just have a switch from the factory.

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Originally Posted by RUGER761

Only if the two batts match can you run them combined the full time, if not identical (one starting one deep cycle) need to separate while the engine is not running, combined when the engine is running so both charge. Does your LSV have a charging relay or charging diode wired in? Most just have a switch from the factory.

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yes, there is a voltage sensitive relay in the boat. So driving around the lake the selector should be in position 1? That is what I've been doing since I purchased the boat 3 years ago. When we stop in the lake to float around and swim I change the selector to 2 while the engine is off and the music is playing. I guess this weekend I'll do a load test on both and make sure I didn't accidently switch the batteries around when I put them back in at the beginning of the season.

Ah good deal the relays make it easy. Sounds like just a dead batt then.

Thank you for help. Much appreciated.

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Originally Posted by RUGER761

Ah good deal the relays make it easy. Sounds like just a dead batt then.

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Hi, I was able to do load tests on both batteries this past weekend. Battery #1 was reading 12.5 volts and the load test read the battery was super dead. The needle zipped over and bottomed out. Battery # read 11.9Volts and "weak" on the load test. Both batteries are starting batteries. Should the boat have a deep cycle as the house battery?

I'm thinking of replacing the dead battery with a deep cycle marine battery and move the good starting battery to the number 1 position.

With your charging relay and switch I'd put in a deep cycle for your house battery.

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Originally Posted by RUGER761

With your charging relay and switch I'd put in a deep cycle for your house battery.

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That is the confirmation I was looking for. Thank you. I'll move the starting battery to number 1 spot and put a brand new deep cycle marine battery in the number 2 spot.