Maiden voyage today

[Dave-R]

I have been waiting for over a month now to try out our 2007 Bennington 2075 FSI. Our first time unloading and loading went great. The Admiral did a great job with this ,and was very happy how straight the boat tracked. The 90 hp. Yamaha is so quiet, you almost have to look at the tach to see if it's running. As this is our first toon, I do have some questions for the forum. She topped out at about 22 mph ( GPS ), and 6000 rpm. I am boating at about 5000 ft. This was with Just the wife and I and a full 30 gal of fuel. Should I consider a higher pitch prop, or leave it as it is ? Also the toon seemed to sit quite a bit lower in the back, even at full throttle. I looked at the cavitation plate at full speed, and it was below the water about 4 or 5 ". The motor is set on the bottom bolt holes, and I thought it might not hurt to raise it a couple of inches.
Maybe this is all I get from the boat, do these numbers sound right? I will post some pictures as soon as the Admiral shows me how. As always thanks for your help. I will find out the prop pitch that's on the Yamaha later.

 

[lakegeorge]

Re: Maiden voyage today

I have been waiting for over a month now to try out our 2007 Bennington 2075 FSI. Our first time unloading and loading went great. The Admiral did a great job with this ,and was very happy how straight the boat tracked. The 90 hp. Yamaha is so quiet, you almost have to look at the tach to see if it's running. As this is our first toon, I do have some questions for the forum. She topped out at about 22 mph ( GPS ), and 6000 rpm. I am boating at about 5000 ft. This was with Just the wife and I and a full 30 gal of fuel. Should I consider a higher pitch prop, or leave it as it is ? Also the toon seemed to sit quite a bit lower in the back, even at full throttle. I looked at the cavitation plate at full speed, and it was below the water about 4 or 5 ". The motor is set on the bottom bolt holes, and I thought it might not hurt to raise it a couple of inches.
Maybe this is all I get from the boat, do these numbers sound right? I will post some pictures as soon as the Admiral shows me how. As always thanks for your help. I will find out the prop pitch that's on the Yamaha later.

I would raise the motor before spending any money on props. I would think that you should be running in the mid 20's. What does the chart on Bennington's web site show?

 

[MH Hawker]

Re: Maiden voyage today

Hope things go well, but i do love the first trip out for the year, I have made it a habit to go with a friend and leave ever one else at home. You know just in case you have problems, thats my story and in sticking to it.

 

[Water logged]

Re: Maiden voyage today

What is the max RPM on that motor? At 6000 you should be close to the max, so prop should be correct pitch.

Glenn

 

[Dave-R]

Re: Maiden voyage today

You are probably right about raising the motor first. I checked the prop, and it is an 11" pitch. The Yamaha is rated at 5500 rpm.
I will try to raise the motor and then see what I get . If I'm 500 over rpm now, maybe I could try a 13" pitch to bring the speed up and put the engine in the proper power range.

 

[The Rooster]

Re: Maiden voyage today

You are probably right about raising the motor first. I checked the prop, and it is an 11" pitch. The Yamaha is rated at 5500 rpm.
I will try to raise the motor and then see what I get . If I'm 500 over rpm now, maybe I could try a 13" pitch to bring the speed up and put the engine in the proper power range.

Yes Dave, sounds like you are a bit under propped. 4" - 5" below the surface on the plate seems pretty low. I'd raise the motor first & go from there. Good luck !!!

 

[Silver Eagle]

Re: Maiden voyage today

Before you change anything try trimming the motor. There's a button under your throttle. at about 4000 rpm's try lowering the angle of the motor and watch your rpms then raise the trim see if your rpms get better or not. If you lower it, the back of the boat should come up some. When I'm up to about 5300 rpms I like to get the bow up just a little so it's not cutting the water .I never go over 5500 rpms (90) hp Merc. two stroke.