1977 (85)HP Johnson...Battery drain when cranking.

[chris414]

I just replaced my control box and cables, and made the unfortunate mistake of taking the boat out to the lake when I thought It was fixed. Once in the lake I attempted to crank the motor and emmediately noticed that the battery appeared to be drained of any cranking amps. I looked at the tach and also noticed that when turning the key over to crank motor, the tach would completely go to 0 volts and when I would let off of the crank, it would go back to 10 to 12 volts. After a couple of attempted cranks, there wouldn't even be enough of a charge to close my choke or to turn starter. I do not even understand what I may have done wrong. Also, I was wondering what is the tach supposed to read when charge is ready because mine will not read more than 12 volts? I did fully charge batteries before I went to lake too. Any help on this head scratcher would be appreciated.

 

[Walker]

Re: 1977 (85)HP Johnson...Battery drain when cranking.

I think your battery is shot.

 

[CATransplant]

Re: 1977 (85)HP Johnson...Battery drain when cranking.

I think your battery is shot.

Maybe, or maybe not. Those are also the symptoms of a bad connection at the battery, solenoid, or starter.

Given the information that the boater had just worked on his controls, I'm betting that it's a poor connection. Time to clean things up and try again.

Also, it's always a good idea to start up in the driveway, on muffs, before heading for the lake, especially if you've done work on your boat.

 

[ezeke]

Re: 1977 (85)HP Johnson...Battery drain when cranking.

The tachometer needle should snap to zero when the ignition switch is turned on [run or start]. After that it should not do anything unless the engine is running because it gets the signal from the alternator and has nothing directly to do with the battery or starter.

Beg, borrow or steal a voltmeter and check the voltage at the battery posts with the engine off. Then check the voltage at the battery with the engine running.

If the voltage is OK, carefully examine your battery cables and after attempting to start, feel the terminals for heat that would indicate resistance from deterioration of the cables.

Check, clean and tighten all engine ground wires.

 

[dooma_Flatchy]

Re: 1977 (85)HP Johnson...Battery drain when cranking.

Are you calling your on board voltage meter your tach?..

I'm with Catransplant on this one. check all the wiring for loose connections, also wouldn't hurt to check the starter,

 

[chris414]

Re: 1977 (85)HP Johnson...Battery drain when cranking.

I guess I did......sorry about that. I'm having problems with my tach too, but can fix that(just a small deal with the gray wire connection). I got a little mixed up with the voltage meter. I will sure clean and check all the connections and check for loose wires. Then I will take all my batteries out and load test them. Does that sound about right? I hope that works. I appreciate the help guys.