Futura Mk3 owners: What prop/max. speed? - Page 2

Northern Pike · 27 June 2013, 20:47

I think you guys are right. 33 34 is what I was expecting. At least I'm getting somewhere towards a resolution. Thanks!

Northern Pike · 28 June 2013, 03:21

Raised the motor one more hole. Gained about 200 rpm and about 1 mph, but also had about 200 lbs. less load in the boat. Required a little more attention to trim adjustment as it was a little more prone to ventilation.

C-NUMB · 28 June 2013, 06:17

Firs impression is that You are running wrong size propeller, it has typical pitch /dia figures
for a 90 hp engine. But after checking the evinrude quick reference guide looks like the diameter is right, smallest available is 13. Strange though for such small HP.

Try to borrow a few other make/model of props and further play with the trim, height and weight distribution, that should do the job, it should go faster. Good luck!

Luv2Fly · 12 July 2013, 20:12

Hey, how are you making out with this. I just got a used Mark 3 with a 40hp 4stroke yammy and it tops out at 47kph or 29mph without speed tubes. This is with a 15" pitch prop and some chop on the water.

We repaired a leak on one of the speed tubes and installed them. With the 2 of us and speed tubes we did 44kph. We raised the motor a couple of holes and now we're at 46kph. I need to get a tach to see where we are for rpm.

Northern Pike · 15 July 2013, 00:44

I spoke to the dealer and the manufacturer. I now have a 4 blade 15 pitch prop. Haven't had the chance to try it yet though. Maybe tomorrow.
I don't think I'll be getting any more speed, maybe even less but so far it seems to be the next best choice of what's available from the OEM.
I suspect it will be a good prop for carrying a heavy load such as divers.
If I want speed looks like I'll have to aftermarket for a smaller diameter/higher pitch.

cgoing · 15 July 2013, 03:20

Why a 4 blade prop? Was that what the dealer recommended? I am running a Suzuki two stroke 40hp on a MK 2 Futura and we are clearing 40 mph with an aluminum three blade.

Luv2Fly · 19 July 2013, 04:48

I'm following your prop issue also as I would like to get more top end. Ideally I think I will move to a 60hp or ideally over power with a 70hp as yamaha's 70 has very little extra weight in comparison. The 50/60/70 all share the same motor but the 70 has better valving and has the torque'y gear ratio. I've done some calcs that I will share later. I thought the high torque gear ratios were only for heavy boats but the calcs show that it will make an inflatable go way faster. The 70 has you move up into their line of high pitch props that chuck the water way faster.