The motor:
1994 Johnson 88SPL (90hp without VRO)
The problem:
Battery going dead
I had the battery tested, it tested good but it kept going dead. I would charge it up, it would last about two or three fishing trips, and it would go dead. I thought the rectifier was bad, so I talked to two or three mechanics and they all told me that if the rectifier was bad that the tach would not work, that the tach on that motor runs off of battery pulses not spark pulses. They also told me to look for a possible short or battery draw from somewhere running the battery down. I am an expert when it come to 12v and 24v wiring, its part of what I do for a living, so if there was a short or some electrical draw somewhere I would have found it. I didnt find anything. I had the battery tested several times and was told it was good. I did a load test at my shop and the battery was good, but the consensus from all the mechanics that I talked to said that if the tach is working that the rectifier is good. So I just went ahead and bought a new battery. Still having the same problem. First trip out, now problems what so ever. Second trip out, battery went dead. I run a Lowrance fish finder and it has a voltage sensor in it. I use it since my boat doesnt have a volt guage. When the battery is fully charged, it reads 12.4+ volts. I have that ff run straight to the battery with an inline fuse so that I could get the most accurate reading. When I am running down the lake, the voltage should go up with the rpm's of the motor, but it doesnt. It stays about the same as if the motor is idling, which makes me think the rectifier is weak or bad, but the tach still works and is accurate because it was tested. Anyway, this one has me stumped. I've tested everything I can think of, traced wires, cut power to everything, and still the battery goes dead after a couple of trips.
1994 Johnson 88SPL (90hp without VRO)
The problem:
Battery going dead
I had the battery tested, it tested good but it kept going dead. I would charge it up, it would last about two or three fishing trips, and it would go dead. I thought the rectifier was bad, so I talked to two or three mechanics and they all told me that if the rectifier was bad that the tach would not work, that the tach on that motor runs off of battery pulses not spark pulses. They also told me to look for a possible short or battery draw from somewhere running the battery down. I am an expert when it come to 12v and 24v wiring, its part of what I do for a living, so if there was a short or some electrical draw somewhere I would have found it. I didnt find anything. I had the battery tested several times and was told it was good. I did a load test at my shop and the battery was good, but the consensus from all the mechanics that I talked to said that if the tach is working that the rectifier is good. So I just went ahead and bought a new battery. Still having the same problem. First trip out, now problems what so ever. Second trip out, battery went dead. I run a Lowrance fish finder and it has a voltage sensor in it. I use it since my boat doesnt have a volt guage. When the battery is fully charged, it reads 12.4+ volts. I have that ff run straight to the battery with an inline fuse so that I could get the most accurate reading. When I am running down the lake, the voltage should go up with the rpm's of the motor, but it doesnt. It stays about the same as if the motor is idling, which makes me think the rectifier is weak or bad, but the tach still works and is accurate because it was tested. Anyway, this one has me stumped. I've tested everything I can think of, traced wires, cut power to everything, and still the battery goes dead after a couple of trips.
