Moderated Discussion Areas
ContinuousWave: Whaler Performance
12.75x21 prop 1999 Outrage 17
|Author||Topic: 12.75x21 prop 1999 Outrage 17|
posted 04-30-2001 10:04 AM ET (US)
Does this sound right: 12.75x21 prop 1999 Outrage 17 with 1999 115 Merc 2 stroke?
I don't know if my tach is 100% accurate. At WOT it read close to 5600 and the speedo read over 42mph -- I immediately backed off because WOT is supposed to be 5000-5250 max.
I spoke to a Merc dealer and I can bring the boat over for a bay test. The testing cost $85. They have new model stainless props that they'll sell for $100 below list. If I need to bring down the RPM's I would be going to a 13x22. They said they might have an older style new prop for less money, but I heard the new styles have better safety feature hubs in case you hit something.
Other question: Do engines idle higher when out of water during fresh water flushing?
|Tom W Clark||
posted 04-30-2001 08:48 PM ET (US)
I'm not the Merc expert but a 21" prop already seems tall. What I don't understand is the 12.75" diameter. Usually there is an inverse relationship between diameter and pitch in a given manufacturers line of props. You say the bigger prop is 13" x 22" which is bigger pitch and diameter. Is the prop you have on there one which has been worked on by a prop shop? If so then there might be some blade surface area that has been removed which would account for both the smaller diameter and the engine over reving.
To answer your second question, no, your engine should idle at the same speed out of water as in.
posted 04-30-2001 09:11 PM ET (US)
Dan - In checking the Mercury propeller charts for your engine, it appears you are running Mercury's standard 3 blade aluminium prop. They show weight range of 1400-2300lbs and speed range of 40-47.
For a boat in this speed range, you definitely do not want an aluminium prop.
It also seems that your boat wouldn't run this high of a pitch, but maybe the Merc 115 is a strong engine. With a Laser installed, the engine should be lifted one or two bolt holes up. You will like that prop. Agressive hold-on and good bow lift. The 17 will fly!
If you don't want to spend the money for an SS prop, your only other choice would be to go for the 23" pitch aluminum.
posted 05-01-2001 05:13 PM ET (US)
Dan, not to conflict with Tom, but an engine's idle should be adjusted in the water and in gear! And the idle speed will be a couple hundred rpm higher out of the water (on the hose) due to the lack of a head of water in the engine's midsection.. exhaust is less restricted... etc.. Clark.. Spruce Creek Navy
posted 05-10-2001 08:34 PM ET (US)
Update: I test drove my 1999 Outrage 17 today in calm water, full tank of gas, myself and a closed sun top. 1999 Merc 115 25 shaft with aluminum prop 12.75x21. With engine warmed up, and test repeated 3 times, at WOT tach read 5200 and speed measured 45mph. What are your recommendations for a stainless prop. I'd like to get out of the hole faster. I want one of the new style Merc props with the plastic hub and a spare plastic hub.
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.