Severe battery drain - 1976 OMC 120 HP- GM inline engine

[joebud45]

I recently had my 28 ft. pontoon boat rewired, had the alternator rebuilt,had new gauges,buss bar,fused breaker panel, new gauges, and new battery installed ( marine 850 cranking amps with 125 reserve amps. While underway at 3,000 rpm, volt meter reading 13.5-14 which is fine. When I return to port and cut engine and all electronics off, the battery charge will drop to 10.5 volts in less than 2 hours. I had to put a battery power interruptor on the positive terminal and unscrew it when not using the boat. What could cause such a rapid power drop? If anyone has a wiring diagram that covers all hook ups from the
starting battery to selenoid, starter, alternator back to buss bar, fuse breaker panel, to ignition switch
showing correct placement of positive and negative leads coming off battery,I would appreciate seeing it.

Prior to the rewire of this 33 year old boat, I did not have a battery drain issue. Please help! Joebud

 

[joebud45]

Re: Severe battery drain - 1976 OMC 120 HP- GM inline engine

bubba1235, many thanks for the quick response. Unfortunately, I could not open the attachment. Your original note was sent to my Blackberry and I forwarded it to my desktop
to open and see it. However, got a vencast message from iboats.com that the attachment was not a vaild attachment. Since i am a first time user with iboats, it is probably me just not
knowing how to properly navigate their site. I did contact the web administrator for help.
If it is possible, could you send the attachment to my home account jsjvmj@aol.com

When I get back to the boat, will check voltage and amp draw at the starter assist selenoid.