2520 225 yahmaha 4 stroke where you guys running?

[miky2884]

My dad just bought a 2004 2520 MV with a 225 four stroke on a bracket. We are trying to get the boat dialed in. he is running a 17x151/2 prop and it seems we are getting a significant amount of blow out. On a slightly moderate chop the motor is cavitating pretty significantly.Also any info what you guys are turning at WOT RPM's and speed. Anyone have any experience with this, any info is appreciated.
Also the motor is mounted on the highest holes, Im think it needs to go down a notch.

 

[Brent]

Also the motor is mounted on the highest holes, Im think it needs to go down a notch.

Do you mean hole #1, which is the top hole?

My 02 F225 turns 5700-5800 WOT

 

[Brent]

Did your father have a 2120 or father in law?

 

[miky2884]

yea highest hole I think you are right it needs to go down one.
My father inlaw has a 2120, my father has a 2520, my cousin (bryan2530) has a 2530 and I have a 2320, we almost got em all covered haha

 

[Brent]

Good luck
Is he planning to re prop?
3 or 4 blades ?

 

[warthog5]

17x151/2 prop

Your numbers?

Props are always listed........ Blade X Diameter X Pitch This keeps everyone on the same page. IE: 3 X 15 1/2 X 17

 

[Ludicrous40]

This year I purchased a 2003 2520XL (has the MV) with Yami 225 on a bracket. Currently have the motor raised up one hole from the bottom (still deep), and am running the black painted stainless prop 3x15x17. My goal is fuel efficiency, and I'm not there yet.

Currently my numbers are WOT 5300 to 5400, speed 27 to 28kts (2 on board, 100 gallons fuel, ~500lbs gear). Lately my cruise speed has been about 20 to 24 kts at about 4800 to 4900. I'm hoping for better performance, and was going to raise another hole (motor is still deep), but Dale straightened me out, indicating that I should change the prop first before optimizing the motor height.

I have already talked to Ken at PropGods, but haven't pulled the trigger yet. Ken recommended that I try the Quicksilver Thunderbolt 15 3/4 diameter by 15 pitch. (bigger diameter, smaller pitch).

I don't have blow out problems when turning, but have improved my driving technique tucking the trim in when cornering. Obviously my motor is lower than yours now. I did have a couple "new to me" blow out problems last Friday morning, but I don't want to hijack your post, I'll start another.

Brent, what are you running for a prop on the 2520??

 

[Ludicrous40]

Just realized, it wasn't Brent with the 2520.....

 

[warthog5]

but Dale straightened me out, indicating that I should change the prop first before optimizing the motor height.

I'll disagree here a little. By raising the motor you will free the boat up.....[Less Drag]....Thus in turn the RPM will be higher. Pitch has a direct impact on motor RPM.

If you got the Pitch all good....and then raised the motor... your RPM may be overreving. I've seen this happen.

 

[DaleH]

The most I've ever seen is a measurable 100, maybe 200 RPM increase in RPMs when raising a motor, but since most motors are run too low on RPMs anyway - no biggie IMHO.

As far as the tuning sequence, I'd say it this way - each prop will perform best at a given height. Bottom line though ... until you wear that prop (and hence the pitch) you don't know what that is, so to me - you have to start with the prop. To me starting with the OB height is backwards, but if it works for you - in the end that's all that matters!