mercury 120 jet bad battery, bad starter or bad motor

dice_left

Cadet
Joined
Sep 6, 2010
Messages
23
i have had similar posts up for almost a year, so i'm going to try and brake it down.
I can't get mercury 120 jet to turn over more tan a few times in the water then starter battery and wires get hot and motor builds up too much pressure to turn over.

Battery- original marine with 500 cold cranking amps replaced with new marine with 550 cranking amps. Still have problem

Starer- original would get hot and sometimes get locked up or just spin replaced with rebuilt one. Still have same problem

Wires- Cleaned. still have problem ps sorry about spelling

It mite be something I'm over looking so please help. :facepalm:
 
Last edited:

Fireman431

Rear Admiral
Joined
Sep 17, 2007
Messages
4,292
Re: mercury 120 jet bad battery, bad starter or bad motor

There could be corrosion built up on the wires inside the insulation. Check them.
Verify voltage in the new battery with a multimeter when off and when trying to start.
Have the starter bench tested. Does the engine ever start? Might have been hydrolocked.
 

dice_left

Cadet
Joined
Sep 6, 2010
Messages
23
Re: mercury 120 jet bad battery, bad starter or bad motor

Ya I have tried cleaning everything wire wise and wires are melting while trying to start. Also, yes it will start out of water and From what my my friend says they got lucky and took it out this year. It seems almost like it needs a bigger starter or more cranking power. thanks and please keep talking. I'm all out of ideas
 
Top