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First Run 2550 RCB Yamaha 300

RReaume

RReaume

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Troy, Michigan
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2550 RCB / ESP, Yamaha 300, Hydraulic power steering with power assist, Full vinyl floor, Jump seat, Changing room, Sony Blue tooth, Lighting package, In floor storage, 52" tow bar, Dual Batteries.

First run was today ran the boat about 3.5 hours cruising the North and Middle channels on Lake St. Clair, 5-10mph winds, 1' chop, varying the speed for break in. 

Few issues noted front and side gate gaps.

Horn stopped working after getting wet.

WOT only 5400 RPM 41-42 mph - 3 people full tank of gas and gear (Little disappointed due to the fact that I took a 2550 out for a test drive with ESP and 225 yamaha and reached 42mph with it at WOT) other than that ride was awesome.   

15.5 x 17p Saltwater Series 2 stainless prop (Prop Bennington recommended with setup)(This prop is the one used on the performance bulletin and said Test weight includes 1/2 tank of fuel, 2 batteries, safety and test equipment)

Anyone think something is wrong or just pitch needs to be adjusted.   

Talked to the service at Miller Marine, they are going to change to a 15 pitch prop (he was even surprised that the prop had to be changed) to increase the RPM's and repair horn (said its a common problem) 

Comments about the RPM's please not sure if anything I might be missing
 
Sounds like you had a day similar to mine. I was only able to hit 38 with mine. Trying to dial it in as well. Going to a 15 should help bring up the rpm's.
 
Check the engine height... perhaps that prop is buried. You should be able to see the cav plate at cruise (not necessary for WOT). A 300 should have no problem spinning that prop IMHO.
 
Might contact Bennington tomorrow morning and ask their opinion.  I believe mine is set up on the first hole.
 
You are not alone in your performance expectations for a new boat.  Acccording to available performance data on my new rig the WOT speed should be around 50 mph.  Best I've seen thus far is 45 mph gps at 5800 rpms.  Yesterday at about 84 degrees WOT was 44 mph at 5650/5700 rpms.  Dealer says he will test other props like the Viper prop which will give higher WOT speed but less economy than the current Rebel prop at cruise/midrange speed which is where most of my use is.  Sounds like the proverbial "can't have your cake and eat it". 

Hopefully just another prop will get you where you want to be in performance.
 
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Probably obvious but always check the simple things first.  Are you using the trim effectively? 
 
I was using the trim you could even feel when there was less drag on the boat. Thanks for mentioning though.
 
To set the trim, I just slowly nudge it while keeping an eye on my Garmin, when I am at max speed I know it is right.  Seems top performance for me is about 3/4 up on the trim gauge
 
One important thing, without a reference to where the motor angle is for given trim, the others' gauge setting isn't helpful.  Mine is completely user and dealer adjustable for range so it could be anything.

I used to love dialing in trim on my I/O boat, which was much like a bass boat with pad bottom, very delicate in the settings. So, I became pretty experienced at it. With the Benny, I spent several weeks trying to figure it out. I'd trim to a point where I could hear and feel it loosen up a little, then the next step up it porpoised like crazy, depending on water conditions. I certainly didn't want to grenade my new motor for lack of water though. At some point I braved going beyond that porpoising point to see what happened. What do ya know, it stopped the porpoise, took off, loosened right up a couple hundred more rpm. Basically, I had to drive through it while still watching the water pressure reading and everything was fine. About 2.5 more mph was the result and it still handled great, no blowout. Who knew?
 
So you think that could be my issue? I'd hate to have the dealer come out the 2 hour trip if I am not trimming enough. It would start porpoising like a mother though.
 
Hard to say. It's worth noting though that the first 47-48mph on my boat are simple. Just nail the throttle, give a little nudge to the trim and you're there in a matter of seconds. That last 2-3 to 50 is ALL trim and takes just the right water and set on the trim up to balance it out. My thought is for yours that first hit to about 41 mph should be very straight forward, assuming you can get the 15 pitch up to 6000 rpm. That's about 11% slip. I'm at about ~11% slip on mine (6250 rpm, 51mph, 18 pitch) which is about as much as is possible from the combo.
 
TomS said:
One important thing, without a reference to where the motor angle is for given trim, the others' gauge setting isn't helpful.  Mine is completely user and dealer adjustable for range so it could be anything.


I used to love dialing in trim on my I/O boat, which was much like a bass boat with pad bottom, very delicate in the settings. So, I became pretty experienced at it. With the Benny, I spent several weeks trying to figure it out. I'd trim to a point where I could hear and feel it loosen up a little, then the next step up it porpoised like crazy, depending on water conditions. I certainly didn't want to grenade my new motor for lack of water though. At some point I braved going beyond that porpoising point to see what happened. What do ya know, it stopped the porpoise, took off, loosened right up a couple hundred more rpm. Basically, I had to drive through it while still watching the water pressure reading and everything was fine. About 2.5 more mph was the result and it still handled great, no blowout. Who knew?
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Yups, my Donzi Sweet 16 used to porpoise starting at 45 and I'd drive right through up to 65! Took balls of steel that first time. It sure used to elicit screams from passengers!!!
 
Just talked to Bennington. They saidthat is the exact setup the did their test with and said it sounds like I am running heavy in the water they recommend pulling the boat out and checking for water in the toons and making sure nothing is dragging. Not what I wanted to here but I guess I have to start somewhere.
 
Easier to drain/weld a toon than argue with the motor manufacturer that the motor doesn't work.  Especially when it runs...
 
lakeliving said:
So you think that could be my issue? I'd hate to have the dealer come out the 2 hour trip if I am not trimming enough. It would start porpoising like a mother though.
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I hit my top speed just as it starts to porpose.  If you porposed (which you said you did) then I would say you have already tried trimming out as much as you can.  Maybe you have some fine tuning to do to hit that top speed, but you should be closer than 7 mph to it.  Like Tom said, (but for me with just a 150) it's that last 1 mph that you have to fine tune the trim to squeeze out.  You're not even close.  You should be hitting ~43 easily (and always) and then that last 1-2 mph takes fine tuning of the trim.   You have something else going on.
 
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Fuel can definitely effect engine performance.   Any chance the fuel is old, lower octane than required, higher ethanol percentage, etc.?
 
Fuel doc. No ethanol mid grade. Just filled it up. Mechanic is going to the boat on Saturday to check everything out especially if the motor is mounted in the right hole
 
Was at the dealer today and found out my motor was mounted all the way down and needed to be up one hole. They pulled it out and fixed it right away but I was not able to test it due to the fact of t - storms. This whole week is calling do rain too. Now the waiting game to test.
 
Looking forward to seeing the result. I am waiting to hear back from my dealer on when he is coming out to take a look.
 
Ran the boat today with the motor in the second hole. 15.5 X 15 salt water series 2, 1 person, 1/2 tank of fuel. 2-3 foot waves. 5600rpm 42mph. We are switching the prop out to a 14.25 dia 17 pitch. Will update with next test drive.
 
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