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Author Topic:   Prop size for 18' outrage

george nagy posted 04-09-2002 03:20 PM ET (US)
Well I just picked up two newer omc 150's to replace my old 150 evinrude.
I'm thinking to use the counter rotated motor instead of the right hand rotation.
The motors came with ss 14.5 x 19 props.
Because my old motor had/has electrical issues I was not able to see which prop works best at proper rpm range ( I have 2 14.5 x 19 and a 15 x 17 I think, both right hand.
The problem is If I mount the cr motor I will not be able to test prop sizes and I think I only want to mount one engine one time.
Surely someone on this website can tell me what prop they run with a same or similar setup.
Any input here will be greatly appreciated.

NEVER SCARED posted 04-09-2002 03:55 PM ET (US)
George
We have the same boat and engine. I tried a 14.25X19 ss prop but rpms were low (4600) so I traded it for a 14.25X17 and now rpms are about 5100. Lots of bow lift with that 19" prop, but engine couldnt breath right. Both props are the renegade offshore 4 blade. Cavitation plate is a bit below the keel. Too lazy to change!
Peter posted 04-09-2002 05:46 PM ET (US)
George,
The 1987 Johnson 150 on my old 18 Outrage used to turn 14.25 x 21 OMC Raker to 5000 rpm with the engine mounted two holes up instead of the standard one hole up. At one hole up I think the 19" should be the right prop, the 17" is likely to be too short. Sounds like NS' engine is mounted too low.
Tom W Clark posted 04-09-2002 08:01 PM ET (US)
George,
The 14.5 x 19 props you have now are probably what you want.
My 150hp Outrage 18 used a 19" pitch OMC SSTII which was perfect, put the rpm's at the top of the WOT range when lightly loaded. I tried a 21" prop at one point and it was clearly too tall a prop.
Obviously, we are talking three bladed props here as a four bladed prop would necessarily have a lower pitch.
By the way, the standard (Whaler recommended) mounting is one hole up.
lhg posted 04-10-2002 04:16 PM ET (US)
George - why not put both of them on the boat? Then you'd have a MACHINE!
But seriously, though, with Mercury, a different throttle/shift control is necessary for the CR engine, and what you are doing could not be done. Don't know how the OMC CR gearcases are configured. You might look into this, or maybe someone here knows.
peteinsf posted 04-10-2002 04:23 PM ET (US)
On the OMC 140 and 200CRs the shift controls are the same as the standard unit.
padrefigure posted 04-14-2002 10:51 AM ET (US)
My 1987 Evinrude on 18 OR turns a 14.75 X 19 three blade SS Viper to 5200 rpm. Good luck in getting your new set-up running.
tlynch posted 05-13-2002 09:41 PM ET (US)
I took a look at my prop this weekend, I have a 1985 Outrage 18 and a 1985 Johnson 150hp. The prop is:
V6-8 OMC Stainless Steel-SST II Propeller. 15 in. diameter x 16 in. pitch [P/N 389925]
Top speed is 42 MPH. WOT is close to 6000 RPM (What I remember from last season).
The blades are "Double Cupped" which "...let the user trim out more for greater speed." I have NO clue what this means.
This is the prop that came with the boat when I bought it last year.
Todd
acseatsri posted 05-14-2002 10:50 AM ET (US)
I think you're underpropped unless you run with big loads or ski. I have a 14 1/2 x 19 stainless, turn 5200@ about 46 mph. Bottom painted. My 1988 150 Evinrude top end is rated at 5500 rpm.
wry posted 05-18-2002 12:13 AM ET (US)
I would appreciate any advice you might offer in choosing a faster prop for a 13 foot BW with a 50 hp johnson. The current prop has plenty of torque and will pull a skier easily but will go only about 20-22 mph. I read here and there that such a boat should go 38-40 with the correct prop. Any counsel?

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Author	Topic: Prop size for 18' outrage
george nagy	posted 04-09-2002 03:20 PM ET (US) Well I just picked up two newer omc 150's to replace my old 150 evinrude. I'm thinking to use the counter rotated motor instead of the right hand rotation. The motors came with ss 14.5 x 19 props. Because my old motor had/has electrical issues I was not able to see which prop works best at proper rpm range ( I have 2 14.5 x 19 and a 15 x 17 I think, both right hand. The problem is If I mount the cr motor I will not be able to test prop sizes and I think I only want to mount one engine one time. Surely someone on this website can tell me what prop they run with a same or similar setup. Any input here will be greatly appreciated.
NEVER SCARED	posted 04-09-2002 03:55 PM ET (US) George We have the same boat and engine. I tried a 14.25X19 ss prop but rpms were low (4600) so I traded it for a 14.25X17 and now rpms are about 5100. Lots of bow lift with that 19" prop, but engine couldnt breath right. Both props are the renegade offshore 4 blade. Cavitation plate is a bit below the keel. Too lazy to change!
Peter	posted 04-09-2002 05:46 PM ET (US) George, The 1987 Johnson 150 on my old 18 Outrage used to turn 14.25 x 21 OMC Raker to 5000 rpm with the engine mounted two holes up instead of the standard one hole up. At one hole up I think the 19" should be the right prop, the 17" is likely to be too short. Sounds like NS' engine is mounted too low.
Tom W Clark	posted 04-09-2002 08:01 PM ET (US) George, The 14.5 x 19 props you have now are probably what you want. My 150hp Outrage 18 used a 19" pitch OMC SSTII which was perfect, put the rpm's at the top of the WOT range when lightly loaded. I tried a 21" prop at one point and it was clearly too tall a prop. Obviously, we are talking three bladed props here as a four bladed prop would necessarily have a lower pitch. By the way, the standard (Whaler recommended) mounting is one hole up.
lhg	posted 04-10-2002 04:16 PM ET (US) George - why not put both of them on the boat? Then you'd have a MACHINE! But seriously, though, with Mercury, a different throttle/shift control is necessary for the CR engine, and what you are doing could not be done. Don't know how the OMC CR gearcases are configured. You might look into this, or maybe someone here knows.
peteinsf	posted 04-10-2002 04:23 PM ET (US) On the OMC 140 and 200CRs the shift controls are the same as the standard unit.
padrefigure	posted 04-14-2002 10:51 AM ET (US) My 1987 Evinrude on 18 OR turns a 14.75 X 19 three blade SS Viper to 5200 rpm. Good luck in getting your new set-up running.
tlynch	posted 05-13-2002 09:41 PM ET (US) I took a look at my prop this weekend, I have a 1985 Outrage 18 and a 1985 Johnson 150hp. The prop is: V6-8 OMC Stainless Steel-SST II Propeller. 15 in. diameter x 16 in. pitch [P/N 389925] Top speed is 42 MPH. WOT is close to 6000 RPM (What I remember from last season). The blades are "Double Cupped" which "...let the user trim out more for greater speed." I have NO clue what this means. This is the prop that came with the boat when I bought it last year. Todd
acseatsri	posted 05-14-2002 10:50 AM ET (US) I think you're underpropped unless you run with big loads or ski. I have a 14 1/2 x 19 stainless, turn 5200@ about 46 mph. Bottom painted. My 1988 150 Evinrude top end is rated at 5500 rpm.
wry	posted 05-18-2002 12:13 AM ET (US) I would appreciate any advice you might offer in choosing a faster prop for a 13 foot BW with a 50 hp johnson. The current prop has plenty of torque and will pull a skier easily but will go only about 20-22 mph. I read here and there that such a boat should go 38-40 with the correct prop. Any counsel?