I have a rebuilt 2.5 litre 200hp 1994 Mercury offshore motor on my boat I bought last month. It has a carburated engine and I mix gas and oil 50:1. The battery is an EverStart with 500 cold cranking amps and 625 mariine cranking amps. The motor was rebuilt by the previous owner, a Mercury certified mechanic. It smoked (white smoke) some at start up in the beginning, but he said that was because the gas/oil mixture was rich for the new motor during break-in. Since then I have mixed it at 50:1 and it smokes a little at start up but is quickly gone. Here is the point of my question. When I crank it, is sounds like it barely is turning over. Heck, it kinda scared me at first because that sound on my pontoon would mean a weak battery! She fires up everytime though, no problems in the month I have owned her. It just takes some getting used to hearing that. I know this may be a silly question, but I have only owned two boat in my life and this is the biggest motor by far on any of them!! Does this big of a motor just turn over slower than smaller ones or do I need to add more cranking power? Your knowledge and help is greatly appreciated!!!!!!!!!!