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ContinuousWave: Whaler Performance
14.5 x 19 prop on a 18/19 Outrage with 150hp
|Author||Topic: 14.5 x 19 prop on a 18/19 Outrage with 150hp|
posted 05-12-2003 07:34 PM ET (US)
I recently bought a 1991 Outrage 19 (classic hull and liner). The boat has a 1991 Johnson 150hp. Yard maintained. 416 original hours. 110 compression in all cylinders.
I had the boat out in the North River of Marshfield/Scituate, MA for the first time Sunday. The boat had 3 Dads, 3 kids (giving the Moms a break!), ~40 gallons fuel and an erected Mills bow dodger.
Opened up, but not fully trimmed, the boat hit 43mph at ~5700 RPM running a 14.5 x 19 stainless steel propeller. This was indicated by the OMC water pressure speedometer and tachometer. The boat also porpoised a bit (despite 600 pounds of Dad around center console).
I am not disappointed with the speed, but I am concerned of the high RPMs achieved despite the bow dodger's drag and the moderate load. Redline is 5,500 right? If I were alone, would I spin 6,000+ RPM?
Anywho, should I be looking at another prop or is the boat setup well (just stay away from WOT when alone).
Thanks a million, Ed
p.s. - the hole shot was awesome!
posted 05-13-2003 11:58 AM ET (US)
Take the prop to a prop shop & tell them exactly whats going on, tell them to add some cup to the prop to bring the rpms down about 300 rpms.
I don't advise having them add pitch to the prop.
Or see if they have a 14.50 x 21, this will bring her back down to where she belongs [ 55 - 5600 ]plus give her more top end speed.
posted 05-13-2003 12:27 PM ET (US)
redline is 5500 so have the tach checked first, then the prop. If prop really is a 19" step up to a 21".
posted 05-14-2003 08:39 AM ET (US)
Tach is good compared to a known good spare.
So would the next prop I try be a 14.5 x 21? Seems like an aweful big prop. I spun a 14.25 x 17 on my old 20' Outrage with Yamaha 150hp.
posted 05-14-2003 12:01 PM ET (US)
Yep, a 14.50 x 21 does sound like an awfull lot of pitch for a 150 on that boat, but if your tach is correct, thats your guide.
Seems like alot of slippage to only get 43 mph at 5,700 rpms.
The best thing for you to do is try a 14.50 x 21 & see how she likes it.
posted 05-14-2003 01:36 PM ET (US)
What condition is the prop in? It could have been worn down to where the diameter is smaller. This could cause the high RPMs that you are seeing. If the prop looks good, try the 21"...
posted 05-14-2003 08:04 PM ET (US)
Tom: The prop is in A1 shape... No dings, nicks, etc.
Sal: There may have been some extra slippage due to a high aerodynamic coeficient of drag as I had the Bow dodger in place and 3 200 (+) Lb guys sailing around the Center Console.
The motor is a 1991 Johnson 150hp "Silver Star", which I have been told is a "hot" motor. Basically a 175hp, with 150hp stickers. I am not gullable, but.........
Thanks again, Ed
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