2004 Yamaha 115 4stroke prop opinions

[Jhwaco]

I recently purchased a 2005 19 fr CC with Yamaha 115 4 stroke. It has stainless steel 3 blade that reads 19k. From dead stand still to WOT it takes about 10 seconds to plain. The RPMS soon as you hit the throttle is around 4000. With the motor trimmed up to where the prop starts to break lose is about 5200. Speed is around 32 mph. I’ve noticed the boat doesn’t change much on pitch between trimmed down or up. The rpm is around 150 difference. I’ve also jacked the boat up high in front trying drain it thinking maybe the hull had water.

could someone give lead me in the right direction. I was looking into four blade props but don’t know which one to go with. I’d rather have more hole shot and plain than top end speed. Also could the engine not be performing correctly? Idling and running across the lake the engine runs smooth to me but doesn’t pick up rpms quick on take off it. Thanks in advance

 

[flyingscott]

It sounds like you are overpropped to begin with. Look at your owners manual but I believe your motor should be running closer to 6000 rpm.

 

[ahicks]

I agree the 19p prop might be too much as well. Thinking the max rpm is 6k too. My experience though, has been that the 4 strokes start sounding pretty busy at that speed, so unless you are in need of max performance (a lot of water skiing for instance), propping for about 5500 works much better. Motor doesn't sound near as busy and it may even be a hair faster.

Sounds like a 4 bladed prop might be a good plan for you. Unfortunately, because of the wide variety of props available, there's no cast in stone rules for converting 3 blade performance to 4 blade. It's pretty much "best guess".

Based on that, with no other info available, I'd be tempted to try a 17p 4 blade. Solas has an inexpensive line of alum. 4 blades. Something like that may be the way to go rather than rolling the dice on a much more expensive prop only to have it turn out to be the wrong one. -Al

 

[Sea Rider]

Why would you like to play excessively trimming the motor up or down. According to the Owner's Manual the combo should work top with its hull riding parallel to the water level, with deck load evenly distibuted and motor trimmed at 90 deg angle (neutral trim) once on plane. If the motor sits at the Hot Spot transom/lower leg height that's having no back water splashes out transom nor prop aeration whatsoever, the motor is running overly pitched up.

Have not seen so far a factory/dealer prop installation that produced excessive over revving, both takes care installing medium pitched props just in case the motor goes to kabum territory.. Selecting a prop that works top it's entirely the owner's homework..

If the motor is revving max 4K assuming that's running strong and healthy, will ned to drop several less pitch props while maintaing 3 blade ones in alu or SS ones if liking them to pull wot revs towards middle to max wot rpm range Yamaha stated which should be between 5500 to 6000 safe rpm range.

Happy Boating

 

[Faztbullet]

Why would you like to play excessively trimming the motor up or down. According to the Owner's Manual the combo should work top with its hull riding parallel to the water level, with deck load evenly distibuted and motor trimmed at 90 deg angle (neutral trim) once on plane.​

It does not state any of the above in owner/operation manual for this motor