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Author Topic:   90hp Prop on Newport

NedsPoint posted 11-17-2004 09:21 AM ET (US)
Regards All - I have been snarfing around the site for several weeks now trying to decide the correct prop for my "new" 90hp V-4 Johnson on my mid 80s Newport. Its a repower job thats going to occur next week. My mechanic friend (old time OMC mechanic - great guy!) insists we should put a 19 inch prop on. He does not want to over-rev the motor. I want a good middle of the ground prop...medium speed, medium torque. Most of the posts I have found here lean heavily towards a 17 inch prop.
Will a 19 inch prop make it a turtle? Thx
John O posted 11-17-2004 10:24 PM ET (US)
ss or aluminum ? I am turning a 19 SS on my Mercury 75hp 2 stroke with a max rpm of 5200 and was turning a 21 Aluminum.
NedsPoint posted 11-18-2004 06:30 PM ET (US)
aluminum
NedsPoint posted 11-18-2004 06:31 PM ET (US)
5200 sounds low - I would imagine 5500 is around spec for the motor
John O posted 11-18-2004 06:54 PM ET (US)
the specs on the Mercury 75hp 2 stroke is 4750-5250, the 90 hp, which is the same motor tuned differently is 5000- 5500 rpm.
My Mercury 75hp 2 stroke 2001 model spins at 5200 with a SS 13 1/4 x 19 which is almost dead on.
The Alum 12 3/4 x 21 spun about 5000 RPM which is why I went to the SS
The Judge posted 11-19-2004 11:32 AM ET (US)
17" stainless or aluminum for a 90hp on a newport. You will get about 5300 and redline is 5500. With a 115 you would run a 19"
NedsPoint posted 11-19-2004 06:50 PM ET (US)
hmmmm - everybody sure??? I have to make the decision early next week. This guys is a OMC mechanic and really want the 19...concensus seems to be 17. I can force the issue
masbama posted 11-20-2004 11:57 AM ET (US)
I started with a 19" Aluminum prop on my Montauk powered by a 2002 Johnson 2 stroke. With me alone top speed was 46+mph @5000 RPM's. When I has a full boat load I could only get 4600rpm's so I switched to a 17" prop. 5500rpms with myself and 5100 with a full house. Go with the 17" By the way-my dealer picked the 19".
NedsPoint posted 11-21-2004 06:28 AM ET (US)
Ok - bought a 13.25 x 17 today....when the ice melts, I'll give her a test. Thx all.
davej14 posted 11-23-2004 10:26 AM ET (US)
John O
What specific ss prop model are you running? I have the same motor and am at 5400 WOT with an 18" pitch SS Vengeance. This is a little high, but as you said, the motor is the same as the 90 hp 2-stroke rated at 5500 max so I don't worry about exceeding the 5250 recommendation. On the other hand, your 19" prop seems just right.
I'm also curious about your speed at WOT with the 19" SS vs. the 21" aluminum and would appreciate your comments.
davej
jstachowiak posted 11-23-2004 10:26 PM ET (US)
The Judge, your advise gives away your identity, your profile confirms it.
NedsPoint posted 11-24-2004 06:06 PM ET (US)
are you guys now saying I should go with the 19 inch pitch like my mechanic wanted to? I can return it, but times running out.
John O posted 11-24-2004 06:43 PM ET (US)
davej14.
www.dansdiscountprops.com

Michigan Rapture.
Not sure of the speed, but I am happy with the way it seems to "grab" the water. Excellant hole shot as well.
Dan's had the best price around and were a pleasure to deal with.

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Author	Topic: 90hp Prop on Newport
NedsPoint	posted 11-17-2004 09:21 AM ET (US) Regards All - I have been snarfing around the site for several weeks now trying to decide the correct prop for my "new" 90hp V-4 Johnson on my mid 80s Newport. Its a repower job thats going to occur next week. My mechanic friend (old time OMC mechanic - great guy!) insists we should put a 19 inch prop on. He does not want to over-rev the motor. I want a good middle of the ground prop...medium speed, medium torque. Most of the posts I have found here lean heavily towards a 17 inch prop. Will a 19 inch prop make it a turtle? Thx
John O	posted 11-17-2004 10:24 PM ET (US) ss or aluminum ? I am turning a 19 SS on my Mercury 75hp 2 stroke with a max rpm of 5200 and was turning a 21 Aluminum.
NedsPoint	posted 11-18-2004 06:30 PM ET (US) aluminum
NedsPoint	posted 11-18-2004 06:31 PM ET (US) 5200 sounds low - I would imagine 5500 is around spec for the motor
John O	posted 11-18-2004 06:54 PM ET (US) the specs on the Mercury 75hp 2 stroke is 4750-5250, the 90 hp, which is the same motor tuned differently is 5000- 5500 rpm. My Mercury 75hp 2 stroke 2001 model spins at 5200 with a SS 13 1/4 x 19 which is almost dead on. The Alum 12 3/4 x 21 spun about 5000 RPM which is why I went to the SS
The Judge	posted 11-19-2004 11:32 AM ET (US) 17" stainless or aluminum for a 90hp on a newport. You will get about 5300 and redline is 5500. With a 115 you would run a 19"
NedsPoint	posted 11-19-2004 06:50 PM ET (US) hmmmm - everybody sure??? I have to make the decision early next week. This guys is a OMC mechanic and really want the 19...concensus seems to be 17. I can force the issue
masbama	posted 11-20-2004 11:57 AM ET (US) I started with a 19" Aluminum prop on my Montauk powered by a 2002 Johnson 2 stroke. With me alone top speed was 46+mph @5000 RPM's. When I has a full boat load I could only get 4600rpm's so I switched to a 17" prop. 5500rpms with myself and 5100 with a full house. Go with the 17" By the way-my dealer picked the 19".
NedsPoint	posted 11-21-2004 06:28 AM ET (US) Ok - bought a 13.25 x 17 today....when the ice melts, I'll give her a test. Thx all.
davej14	posted 11-23-2004 10:26 AM ET (US) John O What specific ss prop model are you running? I have the same motor and am at 5400 WOT with an 18" pitch SS Vengeance. This is a little high, but as you said, the motor is the same as the 90 hp 2-stroke rated at 5500 max so I don't worry about exceeding the 5250 recommendation. On the other hand, your 19" prop seems just right. I'm also curious about your speed at WOT with the 19" SS vs. the 21" aluminum and would appreciate your comments. davej
jstachowiak	posted 11-23-2004 10:26 PM ET (US) The Judge, your advise gives away your identity, your profile confirms it.
NedsPoint	posted 11-24-2004 06:06 PM ET (US) are you guys now saying I should go with the 19 inch pitch like my mechanic wanted to? I can return it, but times running out.
John O	posted 11-24-2004 06:43 PM ET (US) davej14. www.dansdiscountprops.com Michigan Rapture. Not sure of the speed, but I am happy with the way it seems to "grab" the water. Excellant hole shot as well. Dan's had the best price around and were a pleasure to deal with.