F115 performance question

[Northbaptiste]

I just bought a 2005 Skeeter Sl 180 with and 05 F115 on it
Has a 19 pitch prop and seems to be sluggish out of the hole .
WOT with trim revs around 5700 - 5800

Wondering if a 4 blade prop would help

[pstephens46]

Did you have a two stroke motor on a similar boat previously? That F115 will not jump like a 6 cylinder 2 stroke. You should get less noise and better fuel economy I would hope. Maybe some prop expert will chime in. Sounds like it is running pretty well.

[Northbaptiste]

Did you have a two stroke motor on a similar boat previously? That F115 will not jump like a 6 cylinder 2 stroke. You should get less noise and better fuel economy I would hope. Maybe some prop expert will chime in. Sounds like it is running pretty well.

This is my first 4 stroke and this boat is new to me
Maybe I'm expecting too much from it
It is very quiet which I like
Haven't had it long enough to notice fuel economy

[Northbaptiste]

So I have had a few weeks to use the boat .
Overall I really like this motor
Its super quiet
Sips fuel !
Starts instantly

But not overly impressed with performance
With 4 people in the boat I have to lean up on the deck to get it to plane but in it's defence the boat is rated for a 150 so I feel thats what it should have
I'm sure an F150 would make a huge difference

I wonder if the 115 SHO would make a difference on this boat ?

[pstephens46]

You might be able to make some improvement with a prop change. If you re-power, max it out, 150 or whatever the rating might be.

Contact PropGods.com for assistance

[99yam40]

115 hp is 115 hp
if you want better performance you need more HP to turn a bigger prop.

but you need to see if you can get a prop that gets the most from your 115 before giving up on it

[Northbaptiste]

Went to a prop shop today.
Talked to the owner
I was going to go from a 19 to 17 but he suggested going to a 17 but a 4 blade

Tried it when I got home
Big difference
Comes out of the hole so much stronger
I used to have to lean up on th deck to get it to plane when pulling a 3 person tube with 1 spotter in the boat
Not any more
3 people on the tube and 3 in the boat got up and planed in a reasonable amount of time
Much happier with it now.

He doesn't think I should lose much on top end with it being a 4 blade but honestly I don't care if I do
I don't run wide open often anyway

[99yam40]

still need to know if the WOT RPM is good with the load you are running that day, other wise you have no idea if you are lugging.hurting the motor

[Northbaptiste]

still need to know if the WOT RPM is good with the load you are running that day, other wise you have no idea if you are lugging.hurting the motor

Lugging ?
Meaning not turning enough rpm ?
It's a steeper pitch so I can't imagine it not turning rpm
How can that hurt the motor ?

[99yam40]

image you driving you car in high gear all of the time, from start out to higher.
you must get the proper WOT RPM out of the outboard motor even if you do not run WOT normaly. there is no changing gears on it

[Northbaptiste]

So at wot , trimmed up , what should the rpm be
What range ?

[Northbaptiste]

The prop guy said it should only change the rpm by 200

[pstephens46]

If I had a F115 I would want the motor to run 6000 rpm trimmed up with a NORMAL load of fuel, people, coconuts, moonshine, chickens etc.

[Northbaptiste]

I don't really understand the concern
Is it that it may over rev or under rev and lug ?

If anything I think I will have to be careful not to over rev it at wot trimmed

[pstephens46]

Lugging is the concern. Since you can't downshift into a lower gear, it would lug all the time. Straining the motor at all rpm. Yamaha has recommendations for each model. I believe the dealer has to fill out some report for Yamaha when the engine is new. To report WOT rpm with whatever prop they decide to install on the new motor. Helps avoid costly warranty repairs later.... I believe Boscoe reported this at one time. I have never purchased a new motor so I don't know. I do know my F150 will run 5900rpm at WOT. I usually "air" it out once every trip.....