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   I posted a week or two ago about getting a new prop for my 1990 SN, FORD/PCM 351; 1.23:1 Gear; 600 hours.

This boat we use on mountain lakes in Idaho, elevation is 7000 feet.

I wound up getting the ACME 430.

I used the boat Tach (don't have a shop Tach) and my iPhone GPS for speed calcs.  My tank was 3/4 full, in the boat was me and my 15 year old.  It was a sunny, clear day and about 60 degrees air & water temp.  The water was flat calm.

Idle Speed > 650 to 700 RPM
in Gear Forward > 550 to 600 RPM
In Gear Reverse > 650 to 700 RPM
2000 RPM > 13-14 mph
3000 RPM > 26-27 mph
4000 RPM > 34-35 mph
MAX / WOT > 37 mph and 4400 RPM

At WOT, I see a fair bit of white smoke ?  And when running at cruising speed, some whispers of white smoke ?  Not sure I had this before, I didn't notice.

Also, when I went to WOT, I heard a clunk from the engine for a nano-second, didn't hear again, nor did I notice any running issues.

New Prop pulls us out of the water instantly.  The boat is considerably smoother running.  And maybe less wake ?

Are these numbers in the ball park ?

Thanks, cheers, John

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damonwells Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: June-13-2006 Location: United States Status: Offline Points: 87	Post Options Post Reply Quote damonwells Report Post Thanks(0) Quote Reply Topic: New prop results ... Posted: August-31-2012 at 7:44pm
	I posted a week or two ago about getting a new prop for my 1990 SN, FORD/PCM 351; 1.23:1 Gear; 600 hours. This boat we use on mountain lakes in Idaho, elevation is 7000 feet. I wound up getting the ACME 430. I used the boat Tach (don't have a shop Tach) and my iPhone GPS for speed calcs. My tank was 3/4 full, in the boat was me and my 15 year old. It was a sunny, clear day and about 60 degrees air & water temp. The water was flat calm. Idle Speed > 650 to 700 RPM in Gear Forward > 550 to 600 RPM In Gear Reverse > 650 to 700 RPM 2000 RPM > 13-14 mph 3000 RPM > 26-27 mph 4000 RPM > 34-35 mph MAX / WOT > 37 mph and 4400 RPM At WOT, I see a fair bit of white smoke ? And when running at cruising speed, some whispers of white smoke ? Not sure I had this before, I didn't notice. Also, when I went to WOT, I heard a clunk from the engine for a nano-second, didn't hear again, nor did I notice any running issues. New Prop pulls us out of the water instantly. The boat is considerably smoother running. And maybe less wake ? Are these numbers in the ball park ? Thanks, cheers, John

Dreaming Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870	Post Options Post Reply Quote Dreaming Report Post Thanks(0) Quote Reply Posted: August-31-2012 at 9:38pm
	your WOT speed seems pretty low, and your tach, (albiet your dash mount) seems like it could pull another couple hundred RPM. I think your tach may be reading high for the 37mph that you are GPSing. If your engine feels healthy, you might have too much prop. TRBenj is the most knowledgeable prop guy on here, so my opinion may be way off base. just my .02. I am not sure that white vapor is a big deal, with air/water conditions near 60 degrees, that could just be condensation. it's been talked about here a few times. compression numbers on your engine could be helpful to put your mind at ease about a bad head gasket though

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