QSB 5.9 Overprop question

[marks737]

I’ve read all the great info here on engine load/fuel burn etc. After checking my numbers it looks like I’m overpropped. WOT only yields 2890/2950 rpms at 99% load. And my cruise burn numbers are above the curve by 2-3 gph. Engine temps are around 175 deg. No black smoke. Aftercoolers/Heat Exchangers just serviced along with new gear coolers.

Spoke to a prop shop who said WOT should be at least 3050rpm at approx 96% load.

My question is how much pitch to take out and whether it can wait until winter layup or should I haul it immediately and take care of it and lose a couple of weeks. I put about 60 hrs on the boat each season. Thanks.

Your input is appreciated.

2005 390 Sea Ray Sundancer

Topic

[marks737]

Oops! My bad! Thanks

[Steve Lewis]

Mark737,

Gentle Reminder………. You posted last year on this same topic and got some good advice. You might go back and re-read your thread

Question on Engine/Prop load

The advice was exactly the same then as your are getting from Tony now. 2inches

My personal opinion is do it when you haul it out this year for winter storage. Kinda like the advice you got last year 🙂

[marks737]

Thanks Tony. Boat was loaded with 4 small adults, 2/3 fuel, 3/4 water tank.

[Tony Athens]

How Much Pitch to remove ?

Your prop guy is guiding you in the right direction..

How loaded was the boat when you seatrialed it?

Props off the boat–Get them to your prop guy and have them scanned. That is where the answer will come from ………………………… But probably 2″

[Author]

Replies