Id be interested to know the cost to fuel saving benefit of etecs/4strokes etc long term on this size boat?
Think of it this way.. for this sort of boat
1/ how many hrs going to be used per yr?...say use once a month, Thats far more than the ave boat.. say 15 nms out 15 nms in , bit travel in between 10 nms 40 nms
Assume go on good days, well powered well set up (WoT around 37/38 knts) cruise around 30nm/hr
Thats under 1 hr, or under 12 hrs per yr...
Ball park will do about 0.75 to 1L per nm if well set up, so say use 35/40L @ $2:10/ L = about $75 fuel..
Lets assume 4S over 2S is 10% better you have saved about $7 per trip or $84/ yr.
If we add in brand name semi synthetic 2S oil in at 50:1 @ approx $20/ L...about 750ml/ trip thats about 9L per yr $180 per yr.
Then keep in mind 4S oil AND filters are a little more than this per service.... so adding 2S oil if anything on a well used boat makes the fuel difference of $84 per yr even less.
And ave day out in our 5,5m boat very well powered 2S, well loaded up, cruise around the 34/35 knts.. thats a very fast cruise (WoT for most boats that size) and therefore lot more fuel .. ave day out 45/50nms will go thru 45 to 50L fuel plus 1L evinrude oil which we buy by the 20L
Upgrading to a 4S on the justification of economy of say $100/yr...
A smaller lighter boat the savings will be considerably less.