View Full Version : performance question

06-16-2003, 04:36 PM
I bought my first boat last Fall. It's an early 90's Moomba Boomerang and I only had it out once last year. I've had it out three times this year and feel like it's dragging a little- at least according to the speedometers. It tops out at about 30 mph +/- 5. The previous owner nicked the prop and I replaced it before taking it out. He bought it and I've not checked out the size, pitch.... How can I do that? I've been told even the altitdue can affect the shape that should be purchased. Is that true? It doesn't have any problem pulling skiers up so maybe it's a problem with the speedometers. Any suggestions on troubleshooting?

Thanks for any help,

Brian Raymond
06-16-2003, 11:07 PM
Altitude plays a major factor in carb. set-up and prop. size, check with the local dealer for set-ups for altitude. Hopefully, you are set up, if you are, calibrate your speedo setting to 30m.p.h.@3000r.p.m. The speedo pick-ups may also have debris in them, if they do, disconnect the hose from the top, and take a very small drill bit(smaller than the intke port on the front side)and turn by fingers in a counter clockwise rotation to draw out any debris, then, blow by mouth to remove further obsruction. If you feel the motor is not reaching peak r.p.m.(4200-4400) @42-44m.p.h., contact a dealer to run the boat and assess the problem. Brian Raymond

james yarosz
06-17-2003, 04:40 PM
I have a 2003 outback ls. after i broke it in it registered 50+ mph on the speedos.(310 hp carb,3 blabe prop) actual top speed on gps is 42mph.

06-17-2003, 04:55 PM
I broke mine in and calibrated the speedos with the tack method (3800 RPM/36 MPH). Then I took the GPS out in the boat with me to check it and I was about a 1/2 MPH short. Top speed is about 47MPH (320 EFI, 4-Blade Stainless).

Brian Raymond
06-17-2003, 11:09 PM
The carb. motors with the 240-260hp. range, should use the 3000rpm. @30mph. scale. The newer 310-370hp. motors(incl. Vdrives and gear reductions) should use the speedo calibration, 3800rpm.@36mph. The amount of people and gear and ballast will change these numbers some, these figures are based on one person empty boats. If you own or have access to a G.P.S., by all means , adjust accordingly. Brian Raymond

07-01-2003, 05:48 PM
I towed it in to have it checked out before I checked the speedometers. They said they didn't find anything and only charged me 30 bucks labor. I took it out last weekend with the GPS and found out the speedometers were off about 15mph. I wondered why my wife was yelling at me to slow down at 30....

07-01-2003, 10:52 PM
In case you don't have access to a GPS but do have access to a slalom course, you can time yourself through the course and use the following chart to determine your speed.


07-02-2003, 12:22 PM
So you were pulling your wife at 45MPH! WOW! I can't touch that!

07-03-2003, 11:10 AM
I did 55 behind a bass boat once and that was just in a straight line.

Chrispy, if your honey was cutten buoys at 45 she is the bomb...buy that girl another round.