New Engine

[gofastsandman]

Originally Posted by JohnC

You are planning to cruise ~ 60 miles round-trip in "rarely calm" water. That's a tall order for a 20' boat by any standard! I would think that the ability to be on plane at low speed (15 mph or less) would be essential. From what I have read here it seems that even with a 90 ETEC you will top out in the upper 30's and cruise on plane as low as 12 mph if you have to. That's important when you are 20 miles from port and the wind starts to blow. I have not been on a 20 with that power but you could do a search on CSC for Terry England's "Marshtackie". He cruises long range with heavy loads with a 90 ETEC, I think he posted his numbers a while back.
If it were me I would choose the lightest motor I could get. Some of the 4-stroke 115's are pretty light; Mercury is 360# or so - not sure about Yamaha. I personally would be looking at the 90HP ETEC to do the kind of trips you are talking about but I understand that it would be below the "critical minimum HP" in the minds of most people. If I were planning to sell at some point in the future I would want to have a 115; more power is appealing to most buyers.
I would expect to cruise above 4mpg with any of the motors mentioned here.

Min plane speed of 12 is what you want.
I cant get below 16-18 w 365 lbs on a25 in transom
89 20 sf