GandDFreehold
Member
I have twin Mercruiser 8.2 Mag enignes, ser #2A444488 and 2A444506, 506 being the problem child. This is on a 2015 34 PC, with Axius. Went to take the boat out for the 1st shake down cruise of the season. Both engines started fine. While warming up the starboard engine shut down, no alarm. Restarted engine and got low voltage alarm, but it cleared. I ran up the throttles to verify alternator function voltage went up to around 13 VDC, as expected. Things seemed ok, pulled out of our slip, just as I started making the turn starboard engine S/D again, no alarm. This time it wouldn't restart. Good times getting it back into the slip on 1 engine. ( Starboard engine controls steering input, a story for another day) Once I tied up I tried restarting no good, tried parallel switch still NG. I just get a low voltage alarm. Note: when I try starting the engine cranks normal speed, but won't start. I did some quick troubleshooting, Battery voltage with batteries turned on is 12.4 VDC, per Fluke meter, at battery. When cranking, voltage drops to 11VDC at same test point. When Charger is turned on bulk charge is 13.4-13.5, then goes to float.
I've had the charger hooked up and running since late March, prior to launch. Battery terminals are clean and tight, Batteries are 4 years old group 31, AGM, 1150 CCA, 103 AH Northstar.
My question is, at what point does the engine control unit cut out due to low voltage? I know it uses 5 volts to all sensors, I'm wondering if the transformer supplying the 5 volts can't make up due to low input voltage. Hence no alarms, on shut down, only during crank. I checked the alarm history on the Vessel View, the only thing that shows up is low voltage.
I know 4-5 years is about it for batteries but I hate to just throw parts at this and see what sticks.
Right now I left the batteries on full charge, with the charger and batteries off. I'll go back when we get a little nicer weather, early next week, check voltage, the try and start and check voltage again.
Any thoughts? Am I missing anything?
I've had the charger hooked up and running since late March, prior to launch. Battery terminals are clean and tight, Batteries are 4 years old group 31, AGM, 1150 CCA, 103 AH Northstar.
My question is, at what point does the engine control unit cut out due to low voltage? I know it uses 5 volts to all sensors, I'm wondering if the transformer supplying the 5 volts can't make up due to low input voltage. Hence no alarms, on shut down, only during crank. I checked the alarm history on the Vessel View, the only thing that shows up is low voltage.
I know 4-5 years is about it for batteries but I hate to just throw parts at this and see what sticks.
Right now I left the batteries on full charge, with the charger and batteries off. I'll go back when we get a little nicer weather, early next week, check voltage, the try and start and check voltage again.
Any thoughts? Am I missing anything?