I have a Mercruiser V8 350 CID engine in my 21ft Maxum boat. Two or three times a summer the engine will dog out. It always happens at high throttle. It is more than just a "miss". The engine never dies but cuts out to an idle. I simply pull up on the throttle and push down again and I'm on my way. This usually happens after we have run the boat for an extended period of time. It seems to me that when this happens the engine is lacking fuel or perhaps water in the fuel. Any suggestions would be appreciated