repower, need help with pitch

[jackd1023]

1995 Chaparral 1930, 2500lbs aprox

5.0 (250 hp)alpha one gen 2 1.62 gears

now have aluminum black max prop 19 pitch 3 blade

comes out of hole like a champion

Hitting rev limiter at WOT 4800 RPM (Spedo inop, phone gps would not give me speed)

I like the hole shot but while trimmed out bounces rev limiter,

Would it be smart to get a 21 pitch?

 

[Tail_Gunner]

Re: repower, need help with pitch

Sounds right..find a donor prop....No problem huh.... One never know'd until you experiment...5.0 19' boat 22p is not out of sight... But a 21 sounds safe

 

[jestor68]

Re: repower, need help with pitch

A Solas Rubex L3 SS 15-1/4 X 19 will get you off the rev limiter(est -200 rpm), still provide strong hole shot, and run 2-3 mph faster throughout the rpm band.

A 21 would drop about 400 rpm and slow the hole shot.

 

[Tail_Gunner]

Re: repower, need help with pitch

A Solas Rubex L3 SS 15-1/4 X 19 will get you off the rev limiter(est -200 rpm), still provide strong hole shot, and run 2-3 mph faster throughout the rpm band.

A 21 would drop about 400 rpm and slow the hole shot.

Jestor that's a 19' boat fresh 5.0 1.6 gearing...you could be right but that combo runs a 21 7 days a week been there done that many times even a 4.3 will turn a 21 most of the time. But i like the pick.

1.62@4800 19p 10%slip gets 48 now 260hp 19' that a tad slow
1.62@4800 21p 10%slip gets 53 260hp 19' is still slow

Most I/O engines are very weak above 4500 and if you can pop the rev limiter easily generally your two to 3 pitches off

 

[jestor68]

Re: repower, need help with pitch

Jestor that's a 19' boat fresh 5.0 1.6 gearing...you could be right but that combo runs a 21 7 days a week been there done that many times even a 4.3 will turn a 21 most of the time. But i like the pick.

1.62@4800 19p 10%slip gets 48 now 260hp 19' that a tad slow
1.62@4800 21p 10%slip gets 53 260hp 19' is still slow

Most I/O engines are very weak above 4500 and if you can pop the rev limiter easily generally your two to 3 pitches off

The Mercury prop selector comes up with 14-1/2 X 19 SS props suitable for his boat. I suggested the larger diameter Solas to further load his motor and get off the limiter. A SS 21 will definitely get way off the limiter.

Go with what ever you feel comfortable with.