Worse performance with a 17p high five?

[Hurroic]

Hey guys and gals We have a new to us 1992 18ft sea ray Bowrider with a 4.3 mercury v6. The boat came with a brand new aluminum 19p prop which got us on plane pretty quick and had good speed. This prop I only saw 3500 to 3800 rpm at WOT. So I thought I’d try a 17p High five prop. Today I went for a spin and found it took longer to get out of the hole and of course the rpms went up to 4000 rpm at WOT. And seemed slower on plane speed. Any thoughts? I am going to just put the 19p back on as I think the high five would burn more fuel the way it performed for me.

thanks!

 

[Hurroic]

[No message]

 

[WesNewell]

You're way low on wot rpm's. Should be 4400-4800. Which GR outdrive do you have should be on tag, 1.62,1.81. I'd also check tach for proper setting. wot speed?

 

[QBhoy]

You need to check the health of your engine and at least the gear ratio hasn’t been changed from new. I know plenty of boats like this with identical set ups. Most will have a 1.6 or 1.8 ratio even. Both of which will certainly see the rpm right up at or even over 4800 rpm with a 19” and 21” 3 blade respectively.
you are way low on rpm here. Even if you had forgotten to trim up a little...that still wouldn’t account for the lack of rpm you have.