similar to dixxerjim have a 19.5 w/ 4.3 rpm/prop issues19

[starsnstripers]

1988 19.5 cuddy with 4.3 2brrl Mercruiser 184 drive. Came with a 19 P x 14.5 D I got only 30mph @ 4000 rpms and it can rev to 5k easy. I figured i needed more pitch so i went and got a 21P x 14 1/4 D and lost 2mph so i guess the 1/4 less in dia offset the 2" in pitch and made it worse. hard to believe. so do i try to find a 21 x 14.5 or go to a 23P ?

 

[Maclin]

Re: similar to dixxerjim have a 19.5 w/ 4.3 rpm/prop issues19

What are the RPM's at WOT for the new 21p prop?

Just sayin', maybe the 19p was in not so good condition and revved too much. Now the new 21p really bites and the engine is loaded more. In this case a 19p in good condition may give numbers showing that a 19 is the correct pitch yor your setup. All guesswork until you provide the top RPM's and MPH at WOT.

 

[starsnstripers]

Re: similar to dixxerjim have a 19.5 w/ 4.3 rpm/prop issues19

What are the RPM's at WOT for the new 21p prop?

Just sayin', maybe the 19p was in not so good condition and revved too much. Now the new 21p really bites and the engine is loaded more. In this case a 19p in good condition may give numbers showing that a 19 is the correct pitch yor your setup. All guesswork until you provide the top RPM's and MPH at WOT.

I can't get to WOT even with the 21P I dont dare go over 5k. Doing 28mph at 4000 rpms with the 21P. I've run it up tp 5k for a second and had more to spare. Just dont understand how i lost 2mph going from a 19 to a 21P. Both props in good shape and same design.