I am looking at buying a 19 foot Carolina skiff 190 Bay runner (sea chaser)and the dealer has a 60hp yamaha installed on it. Is this motor enough for this size of boat i.e. weight is approx 1680 lbs. and I reallly need to know if he is skimping on the less powerful 90 hp. ?? He offered a test drive and said mid 30mph is about the top speed. Am i getting the shaft or the right deal??