12-02-2017 09:23 - edited 12-02-2017 09:41
I have just read this post and I hope I'm not too late with my reply??? Please let me give you some first hand advice from a current very satisfied I3 90 Etec owner. I have been a long time boater since 3 yrs. old & Evinrude guy. You have stated your Funliner is 600 lbs., right? This is a very light craft. Therefore, with today's fuel injection engine technology, much higher performance can be achieved with less hp. The I3 with 1 less cylinder will, without much doubt, give you everything you're looking for. You don't need to have 10 hp more to perform relatively equal to what you have now!!! I will tell you why.
My rig is a 16' 7" 2014 Alumacraft Competitor 165. Dry boat weight without gas is 1,040 lbs. plus all my equipment , 19 gallons gas, electric bow trolling motor & 2 people (@ another 415 plus lbs.) additional. So, my estimated total weight taking all this into consideration, is 1,500 - 1,600 lbs.! I am running a standard aluminum 13 7/8 dia x 17" prop. My GPS WOT speed is EASILY 37 mph without batting an eyelash!!! Under ideal running conditions, I have reached 39 mph!!! Plus, I've just found out I probably should go up to a 19" pitch to attain optimal WOT. Keep in mind this is with 2 people, gas & all my equipment, etc.!!!
This fuel injected I3 Etec 90 hp (only 10 hp less than your 100 hp) is weighing in at 320 lbs. The difference is 45 lbs., which is comparable to the weight of an extra battery and is easily outperforming your current rig by a lot!!! The weight of an extra battery for the 320 lb. I3 90 Etec in the back of your boat or on your transom is not going to do you any harm. If it becomes necessary for water skiing, just carry a spare lower pitch prop... than what you would normally run. I'm quite sure you'll have plenty of torque to get the job done. Of course, you should always carry an extra prop anyway. On a typical days outing cruising for 4 hrs. at 3.500 - 4,000 rpms I burn between around 5 gallons of fuel. Sometimes SLIGHTLY more. I typically use roughly 5 oz. of oil on the XD100 setting, exclusively.
I mean to tell you this machine is one superb engineering work of art!!! It just quietly hums with a modest & pleasant throaty rumble. No lie or exaggeration, without needing full throttle, I reach plane in about 3 or 4 seconds using only 3/4 throttle!!!
Given all that I have just described from my honest experience, give very serious consideration to purchasing this motor!!! I'm quite sure you'll have little regret. Going to a competition's 4 stroke would be an awful mistake! I know how I sound. I am not connected to or corporately involved with BRP or Evinrude in any way whatsoever. I am just one very satisfied & pleased owner of this excellent product.