1976 40hp evinrude battery question

[hardwater fisherman]

I have 1976 40hp with electric start and a 5amp charging coil. I use a deep cycle battery for everything else. I have been using a car battery for starting, with 625 cca and it worked well but it is 8 years old now and not holding a charge well. My manual states I need a 12 volt battery with 70 ampere hour or better, with a minimum of 2 minutes cold starting capacity at 300 amperes discharge, zero degrees Fahrenheit, and a 10 second voltage reading of 7.5 volts. Will a Walmart marine starting battery 24m-625n with 500 cca work well enough or do I need a larger battery?.

 

[Alumarine]

It will just fine for that motor.

 

[hardwater fisherman]

I thought so. But it is the smallest marine battery they sell so just wanted to know for sure.

 

[gm280]

I actually have that exact same engine. You will be okay with most any battery for that engine. You can see how that engine look in pieces and finished again at the link below if you like...

 

[hardwater fisherman]

Your motor looks very nice. I have 2 one is an Evinrude and the other is a Johnson. The Evinrude was a rope start so I bought the Johnson to convert it to electric start. The previous owner tried to get it running. So I got 2 new coils and a new fuel pump. Mine looks more like your before picture, but it runs very well.