Engine continues to turn over after ignition is shut off

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
I have a 1978 mercruiser 470. I hooked the battery back up to it after it set over winter and tried giving it a start. The motor cranked slowly, as if battery needed to be charged (it has set all winter). I turned it over for about 6 seconds, then released the key. The motor continued to turn over, even after I removed the key completely. I ran to the battery to find the wires getting so hot that it melted the solder inside the connections. I undid the wing nuts and removed the connections as quickly as possible. The connections were correct, reds on positive, blacks on negative. I let it set a few minutes and upon touching the wires back to the terminals, it started to crank again so I removed them again and now here I am.....any ideas? The boat was parked last year and did not ever do this, please note that this is the first time ive tried starting this boat this year...thanx
 

FreeBeeTony

Captain
Joined
May 15, 2002
Messages
3,991
Re: Engine continues to turn over after ignition is shut off

sounds like a possible problem with the ignition switch
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: Engine continues to turn over after ignition is shut off

I would suspect the low voltage burned the contacts inside the starter solenoid and made them stick. Time for a new starter.
 

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
Re: Engine continues to turn over after ignition is shut off

i have a starter solenoid that is seperate from the starter I believe....its a 1978 470 by mercruiser I had said....am I wrong
 

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
Re: Engine continues to turn over after ignition is shut off

one more thing....how do i diagnose the ignition to check for a problem
 
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