like gt said you need to have minimum of 12.5 volts with engine off. If it acts weird after the boats been running, it could be that ur cables are getting too warm and the resistance in them is climbing or they may be too small diameter. I wouldnt suggest a mini starter for ur application. Im running 10.2 to one compression and to be honest I use a run of the mill autozone starter lol that way if it craps out i can go get a new one, they have been very reliable for me. I would check ur battery, if u can you can take it to autozone and they can do a load test on it because even if the volt meter says you have at least 12.5 voltage that could just be surface charge and when it gets with a load it drops to like 8 or even 6. I run an everstart maxx battery from walmart, lol its the big ass 27 series, and its 3 years old, but hell i cant knock it, i leave it unattended for weeks at a time and it starts right up, it even fired the engine instantly after sitting the entire season in the boat lol.
