'82 merc 50, draining battery (new2me)

[jasperpso2]

just got the boat today. '82 mercury 50hp outboard.. i bought a new battery today, and put it in. and headed to the river.. it after a few seconds, it started up.. i let it idle, checked to make sure the water pump was pumping, it was.. so i took off.. it ran pretty good. i cruised for less then a hr, and headed back to the ramp..i shut it down.. got the trailer in position,but when i went to start it back up, crap - the battery is so dead it wont turn over! fully charged, to dead in less then a hour.. i dont figure the engine draws enough electricity powering the coils and plugs, if the stator isnt working, to kill a battery in less then a hr, but i dont really know..

i called the previous owner,and he said he took the battery out without labeling stuff, and when he put the battery back in he wasnt sure he was right?!

my question is - if a wire is on the battery backwards, is it possible the motor would still run like it did? could there be something?? draining strong enough to kill a battery - assuming the outboards stator is putting out amps?

i think i should trace down all the wires going to the battery and make sure they are correct, which wires are required for engine starting and running?

the boat is otherwise in good shape, and i am hoping to get this figured out.. thanks for any help.

also, anyone know what merc service manual i need?

 

[bayfishr1]

Re: '82 merc 50, draining battery (new2me)

had the same problem. don't waste time and money like most do. your rectifier is BAD! it changes the current over to recharge the battery while running. like an alternator. if the terminals neg. and pos. were to even barely touch the wrong posts (backwards hookup), it will destroy the rectifier immediately. try to ask your local marina for any used ones that they have tested.

 

[asm_]

Re: '82 merc 50, draining battery (new2me)

It would have never ran if you hooked it up backward.

If the battery is not getting charged while running, I would first test the recitifer to make sure it is working correctly. A simple multi-meter can be use to do bench test after the rectifier is removed from the circuit. CDI's web site has instruction on how to bench test rectifier.

If the Rectifier tested to be defective, and your stator output is limited to 25A, Radio Shack does have rectifier for less then $5.

http://www.radioshack.com/product/index.jsp?productId=2062584

Now, if your stator output is less then 15A, you may want to consider the snowmobile retificer/regulator unit that Force motor folks are using on their motor. Check the Force forum for more info.

B

 

[Fed]

Re: '82 merc 50, draining battery (new2me)

Are you sure the battery was flat, the motor doesn't need a battery to run so it shouldn't draw any power from it.
Check the connections at the battery, solonoid, starter motor & engine ground.

 

[jasperpso2]

Re: '82 merc 50, draining battery (new2me)

thanks for the somewhat dated responses guys.. fortunately i found out the next day (2 months ago) that some of the wires to the battery were indeed hooked up wrong at the battery, but that wasnt the problem.. found out after i charged it up overnight it still wouldnt turn over.. it wasnt the battery at all, but the starter that was fried.. i just hadnt thought of it since it started the previous time no problem.. 300$ for a quicksilver starter (ouch) and i was fixed right up..

again though i do appreciate your responding.. i shouldve updated the post..