1970 johnson 60 hp questions ?

After a lengthly process of getting my motor running correctly. i just want some advice on how to keep it that way.
rebuilt carbs
new fuel pump
new cdi amp & coil
removed clipper

the questions i have regard a couple of different issues and i also have some concerns
number one is what type of battery i should be using??
in the cdi installation it stated not to use a deep cycle battery (but offered no explanation as to why?)
this has also been mentioned by joe reeves ( with no explanation as to why)

the battery i have is a walmart everstart 27dc-6

another thing that I have read is in regards to adding a 12 volt diode in case the starter is using to much power and robbing the amplifier of what it needs.
I just want to protect my amp and everything i just bought from a failure. any help would be great and thanks in advance.

Re: 1970 johnson 60 hp questions ?

It has to do with the longevity of the battery and the cranking amps. The deep cycles just offer a hotter spark.

As far as the 12V diode, idk. The only thing that I could see that could damage the electrical is pulling the battery cables while the engine is running, but I am fairly new to this.