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proline1128

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"On my 1993 johnson 150hp I am

"On my 1993 johnson 150hp I am turning a 14 1/2 x 19 prop. its on a 1988 21ft wac proline. i can only get wot up to 4200 rpms, so i tried a 15 x 16 prop and ended up doing 6000 rpms at wot. whie running the 19 prop top speed was about 25 to 30 mph, when using the 15x 16 prop top speed was on about 22 mph. Whay size prop should I try next? thinking 15x17. Any recommenditions? thanks!"
 
"I agree. The 17" should p

"I agree. The 17" should put you close to where you need to be. The max. wide open throttle range for your engine is 4500-5500 RPMs. It does sound like the props you are using are either different brands or style though, due to the steep difference in RPM's going from a 19" to a 16". You should have only picked up around 600 RPM's and you picked up 1800..."
 
"Agree with Rick - prop calcul

"Agree with Rick - prop calculator says that a 17 pitch should run well on that set-up, giving you an rpm at wot of about 5200-5300 and a top speed of about 42 mph under "perfect" conditions.

Was your speed measured with a speedo or gps? Also, are you sure your tach is working properly. It does sound rather odd that you would get an 1800 rpm difference out of 3" of pitch - especially since the second prop had an extra 1/2" in diameter...."
 
"I also believed that my 3&#34

"I also believed that my 3" change would only bring up the rpms about 600 as well. I couldn't read the numbers on the prop, my neighbor and I both assumed it was the same size thats on his motor now,because it was his spare I borrowed it from him. I believe my speedo and tach are ok. My mechanic, when he gets a chance will hook up his tach to my motor. Will keep you posted. Thanks for the reply."
 
"Took boat out today. Water ca

"Took boat out today. Water calm, very little wind. For some strange reason was able to get rpms up to 4600. First time this happened. Maybe tach was off a little. Will still look for a 17" prop and try it."
 
Ebay is a fantastic place to l

Ebay is a fantastic place to look for props. I've bought and sold several there with very good results.

KJ
 
"Albert, what diameter/pitch a

"Albert, what diameter/pitch are you interested in? I can post an OEM and Michigan Wheel cross ref number for you...."
 
"Albert, a 15x17 aluminum woul

"Albert, a 15x17 aluminum would be OEM #391200 and a stainless would be #391290.

Michigan Wheel numbers for the same would be 011007 and 013044 respectively (these numbers may be old but should allow for cross reference)...."
 
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