Battery totally dead overnight/ Johnson 90

[SavannahKen]

My 1998 Johnson 90 battery was totally dead after two week's storage. It wouldn't even charge. All switches for the LW and BP were off as were all other items. I had left the drain plug in and there was 6-8 inches of water that had accumulated during that time (rain) and completely covering the float and pump.. I went and bought a new battery thinking that the bilge pump had run and finally killed the battery. I started up the motor and ran it for about 5 minutes but did not take the boat out to sea. I thought all was fine. Well, went to start the motor the next day and the new battery was DEAD! Again, nothing was left on and it had not rained at night and I DID leave the drain plug out this time. My question is: Can a bad voltage regulator slowly drain a battery when the motor is not running? I have noticed that the DC voltmeter on the console reads max when running (16-18 VDC) OR Could 5 minutes of running a motor with higher voltage than normal kill a new crank battery?? Is the VR located where it can be easily replaced? One other item to note is that I bought this boat three weeks ago. It ran great the first two times out. The horn was not working and I quickly found that the positive lead was not connected so I re-connected it. The horn still did not work but I neglected to disconnect the positive lead. Could it be possible that a faulty horn switch/ horn could have drained the batteries? I did disconnect the pos. lead after the second battery was drained down. I appreciate any and all feedback.

 

[mikesea]

Re: Battery totally dead overnight/ Johnson 90

Im going to stick my neck out here.My thought is ,its not eng related.if your keyswitch was off ,no power was going to your ignition.A dead battery overnite is a heavy load.Start by having a well charged battery ,disconnect all cables to the engine,which would be just the large pos and neg.Leave all neg acc.wires on the neg at battery,as you pace each pos.wire back on ,note if you get a large spark,if you do ,find what it feeds ,thats liely the source of the draw. You can do it also with the eng cables,if a large draw is ulling,you will see a good size spark,be sure your area is vented of any gas fumes.If you have a auto bilge pump , it could be wired where your main switch dont shut it down.You may have a couple wires fusd in the boat somewhere.Just a guess.You can also ,remove the eng cables,put your battry back and see if it draws down overnite.Its always possible it is eng related ,but you would likely see burned wires at the voltage reg.or somewhere.

 

[SavannahKen]

Re: Battery totally dead overnight/ Johnson 90

MikeSea,
Thanks for the response. I was going to attempt the very same steps you advise to try but needed to charge the battery first. I am out of town and won't be able to try until Friday evening. I'll let you know how it goes. One thing I WILL be doing this weekend is installing a DC power kill switch. I'm slowly getting there (adding the necessities). I installed a gasoline/water separator filter last weekend as the Seapro did NOT have one and I think water bubbles are the causes of my occasional engine hiccups. I have owned SeaDoo and Yamaha jetSkis before but this is my first real boat.
Thanks, Ken

 

[SavannahKen]

Re:Solved- Battery totally dead overnight/ Johnson 90

Re:Solved- Battery totally dead overnight/ Johnson 90

Found it! The rectifier has a shorted diode in it (Red and Yellow leads). Traced the 2.2 OHMs ON THE POSITIVE FEED TO THE ENGINE main +VDC terminal ALL THE WAY BACK TO THE RECTIFIER MODULE. Zero Ohms between the aforementioned leads. The 2 Ohms through the wiring and the shorted diode was killing the batteries in a couple of hours during the night. Luckily I did not wind up with a dead battery out at sea. Now to spend more money. Where can these be bought? West Marine?

 

[SavannahKen]

Re: Battery totally dead overnight/ Johnson 90

Found a rectifier unit locally here in Savannah (49 bucks) and the problem no longer exists. Took the boat out for a spin and checked again when I got home and all is good. Now back to work on my other problem....