Mercury 18xd with added electric start

[Hawgfan_66]

Hello all,

Thank you for taking the time to read and hopefully respond. I have a mid 80s 18 hp Mercury outboard that I recently purchased used. The previous owner had an electric starter added to it. I am going to be adding a trolling motor to the boat ( 14' x 36" Ouachita jon boat). I plan on using the deep cycle marine battery that is there for starting to also power the trolling motor. I need to know the cranking amps required for the starter in order to determine if I can move the battery and run the wires from the front of the boat for the starter or if I need to leave the battery at the back of the boat and run the wires up front to the trolling motor. I can't find any information or specifications online. Any help would be appreciated.

BTW, I am new to boating. I fished with my father, grandfathers and uncles when I was a child. I know the basics of boating from learning to sail and riding in boats as a child. I enjoy fishing and want to get the most out of my 'new to me' boat.

 

[oldman570]

You would be better off to place the deep cycle battery you have in the front of the boat, and buy another battery for starting the motor. The cost of the extra wire and the chance of one battery being drawn down as to where it will not start the motor would be less costly in the long run. If the motor dose not have the charging coils in place when the starter was added, then that would make things worst. As for the battery to start the motor, a wet cell battery of 350 cranking amps should do the job. It dose not have to be a deep cycle battery, and a good lawn mower batter will work as long as it gets charged by the motor or a maintainer after being used. JMO
Oldman570

 

[Hawgfan_66]

Thank you. I appreciate the comment. The reason I am thinking of the wiring 'fix' is that the pull start does still work on the outboard, paired with the fact that I do have a battery charger that I hook up to charge the battery the night before I go out. The information on the cranking amps you gave me is very useful and I appreciate it. The motor does not have charging coils in place. The starter was added by the previous owner as a convenience. I took the boat out for the first time last weekend and started it multiple times with the pull start on the first pull while I was out.

Thanks again,
Hawgfan_66

 

[MH Hawker]

The cranking amps on a 15 is 55 amps, so most any should be fine.

 

[Mi duckdown]

I would get that pull start fixed. always nice to have in an emergency.