Thank goodness that was the vote of confidence I had been waiting for.

Preliminary #'s

Saw 79mph briefly 2 on board 140 gals of fuel (1/2 tank). Engines are on the limiters but I didn't realize it b/c you don't hear them or really feel it like you do an inboard. I tried to back to back it yesterday & happened to notice that the RPM's flash RED on my Garmin when in the bar graph ENGINE monitoring screen. Sat I was in the FUEL monitoring screen so I didn't notice that. Bottomline is the Merc 350's w/ the Merc Revolution4 25p prop's need more prop on a NT340 BUT that's the largest pitch Merc currently offers in the Rev4. I know you can run bravo's or other but that can require drive height adjustments in order to accommodate the different style prop. My goal is to maximize my package from an efficiency standpoint but remain within warranty specs. A little more pitch would help raise the cruise speed everywhere. Currently the boat gets on plane w/ ease, rolls over w/ minimal throttle effort so no real concern there.

Here's what I got for fuel burn data. I only captured speed & flow rate, I failed you on WOT fuel burn as well as RPM but can get that next time. I was by myself so one of us (ME) had to pay attn to where I was going too!

Lake Norman, 600ft above sea level, slight wash machine type chop, 75 deg, 140 gals & 1 on board.

Instant Fuel Flow:

40mph= 1.5mpg
50mph= 1.4mpg
60mph= 1.3mpg
70mph= 1.0 mph
WOT= 79mph on limiters

I'll get some more info as I get some more seat time & opportunity (weekday boating way easier for documenting performance w/o a gazillion jet ski's)

I also plan to weigh the boat w/ gear & 1/2 fuel, then weigh the trailer empty to see where I'm at overall.

depending on how far over you are in rpms, bblades may be able to raise your current popellers pitch by labbing.. But you should also check your rpms at full load. You may not be able to raise your pitch. Just a suggestion

Good feedback & definitely an option. Only 2 outings to date at the home port so I need to do a little more testing & documenting before I do anything drastic. Supposedly Merc knows that they need to produce a Rev4 27p since the introduction of their new 350's. I just don't know how quickly they'll become available. Labbed 29 B1's have been recommended but I'm going to sit tight a bit.

When I am trimmed all the way up I hit the rev limiters at WOT. I found if I barely tap the drive trim down it takes it off the limiter and my speed increases 1 mph. I decided not to tweak the props because in my case, running twins, getting on plane is already a slow process.

If you start runing special props then you have to have special spares. its best to find an off the shelf prop to suit your needs. I dont see you running wfo that often anyway. Merc should entertain the thought of making bigger pitches, Now the Multi engine 350 & 400hp are gonna run out of prop selection quick...

I'd probably keep the stk 25's as spares.

I'm really after better cruise / fuel efficiency not more top speed but as you raise the top speed normally the cruise will come up some too. I understand at a certain point you loose acceleration & or the ease to get on plane but I'm confident I can find a happy medium. Runs stout currently.

Come to think of it I was running labbed 34 and 36 bravos on my twin 525 eliminator and over time threw a few blades. I have reverted to non lab 34 bravos which are quite a bit less expensive and lost a few miles an hour on top end but saved a few bucks on the replacements as well as having to match the labbing formulas on the replacement. Can't just open the box and throw them on

Boat / Trailer Weight
 

Filled the boat up to 1/2 tank (135gals) then took it to the scales. My off the cuff guess was 13,500lbs for the boat, 1/2 tank of Fuel, Trailer & Gear. I was close, it weighed in at 14,100lbs. If I lost 100 gals of fuel the boat would weigh in at my guesstimated weight of 13,500 which is close to what it weighed on the tow home from SportBoats.

Sounds like your having fun dialing her in! What poker run you hitting next?