2000 310 Sea Ray with inboards - Performance issues?

[ArtWallach]

Hello,
I have a 2000 310 Sea Ray with inboards that are using 16x15's props. I see the Sea Ray website / manual suggests 16x15's or 16x17's. I brought the boat new in 2000, however, the boat was out of my hands for 5+ years. Therefore, I dont know if the boat still is using the original props, but when I got the boat back last year the performance has been horrible. I used to run at 3600 RPM and get 22GPH at 21kts.
Now I run at 3600RPM and im burning 36GPH and running 16kts. The engines have been tuned. The props have been tuned.
I'm puzzled as to what to ask the shop to do for me during commissioning.
Does any have the same boat to talk prop's and performance?
Thoughts?
Art

 

[sea hare]

edit....just read you got it tuned

 

[Air O'Nautical]

Can you achieve the engines recommended WOT?

I'll bet not.

The cover on your motor will give the RPM range you NEED to be able to achieve.
If your light you should be on the higher end of the range.
If your not able to rev out to spec. the question becomes why......

Do you store out of the water? So, that you know the bottom is clean,fair and smooth.
Were the props tuned by a prop scan shop back to spec.? There should be a report that came back with the props. Do the props spin easily by hand with no binding or excessive drag?

If we're good so far...it leads to the engine(s) not putting out their rated HP.

Often a boats engine will get moisture inside that will settle on the valves and cause rust.
Rusty valves don't seal very well and the engine runs ok....but not as well as it should.
Do a compression and leak down test to know the condition.

These are basic ideas that apply to all engines,

Good luck.

 

[ArtWallach]

I'll have to check ... I think WOT is 4800 RPM. I never tried to push it that hard. During the winter lay up of 2012 I had the marina remove the props and send them out to be tuned. I never got a report. I asked dozens of times. Thats the primary reason after the 2013 season I left the north shore marina and brought the boat to my marina on the south shore. Now I'm not locked in using the marina's service.
If I put 6-8 people on the boat, it wont even get up and go. To get the bow down I send people to go sit on the forward berth. I even had the bottom power washed mid season. Didn't really help.

 

[ArtWallach]

YEAR

MODEL

ENGINE OPTION

DRIVE

RATIO

HIGH ALTITUDE GEAR RATIO

PROP SIZE

PART N0.

WIDE OPEN THROTTLE RPM

2000

310DA

T-V Drive 350 MAG MPI MCM Horizon (T-300 PHP)

VEL 5000

1.50:1

16 x 17 3BC

4800

This is off the Sea Ray Web Site...​

 

[Air O'Nautical]

Sounds like you don't really know what happened to your props.
Any chance the boats on the hard and can scan the props now to see what pitch they are?

 

[ArtWallach]

The only info that I was able to get from the marina regarding the prop tuning was that they are 16x15's.