natemoore
Master Chief Petty Officer
- Joined
- Jun 13, 2009
- Messages
- 844
We just bought an '87 Four Winns Horizon 170 with a Mercruiser MCM 165, serial number B648337.
The seller said the battery died on him earlier that day while demo-ing the boat with another potential buyer. He measured the battery voltage with the engine running and got about 13.5 volts, so we both agreed it was just a bad battery.
I put in a new one and took the family out on Santa Rosa Sound in N.W. Florida for a couple of hours. Despite suggestions from the family to beach it across the sound and swim for awhile, I decided not to kill the engine until we were back at the dock. I'm glad that sometimes I can be brilliant because I tried to restart the engine and sure 'nuff: dead battery!
Can I start the engine then disconnect the battery to test the charging system? If it were a car, I could easily confirm a strong alternator by turning on the high beams and a/c blower then disconnecting the battery. If the lights remained bright and the blower maintained speed, I could assume the alternator was putting out juice (I once drove for 12 hours with a bad alternator, but didn't get stranded on the side of the road until nighttime after the headlights drained the battery).
My theory is that if I start the engine, turn on the bilge pump, lights, radio, and blower, then disconnect the battery, if everything continues to run as before, then my charging system is good and my problem is elsewhere.
Sound good?
The seller said the battery died on him earlier that day while demo-ing the boat with another potential buyer. He measured the battery voltage with the engine running and got about 13.5 volts, so we both agreed it was just a bad battery.
I put in a new one and took the family out on Santa Rosa Sound in N.W. Florida for a couple of hours. Despite suggestions from the family to beach it across the sound and swim for awhile, I decided not to kill the engine until we were back at the dock. I'm glad that sometimes I can be brilliant because I tried to restart the engine and sure 'nuff: dead battery!
Can I start the engine then disconnect the battery to test the charging system? If it were a car, I could easily confirm a strong alternator by turning on the high beams and a/c blower then disconnecting the battery. If the lights remained bright and the blower maintained speed, I could assume the alternator was putting out juice (I once drove for 12 hours with a bad alternator, but didn't get stranded on the side of the road until nighttime after the headlights drained the battery).
My theory is that if I start the engine, turn on the bilge pump, lights, radio, and blower, then disconnect the battery, if everything continues to run as before, then my charging system is good and my problem is elsewhere.
Sound good?
