26mph with 19p ss prop@ 4200 - Is this OK ??

[gsrsol84mm]

1980 Glaston Sea Fury with Late 70's 225 Merc 2 stroke, 19 pitch stainless prop. Had it on the water today. The GPS showed 26 mph @ 4200 rpm. Boat seemed to like this RPM for crusing. Not sure of the weight of the boat but there were 4 adults on the boat and the boat has an added T - Top.
The boat tops out at about 40 mph in the 6200-6400 rpm ( Not positive of the top rpm as it was the first day on the water in a while )
Boat really comes out of the hole fast.
Is this and acceptable range ? I do have a 24 pitch SS prop as well but have never installed it. Would it be worth giving it a try ?
Thanks for any feedback.

 

[steelespike]

Re: 26mph with 19p ss prop@ 4200 - Is this OK ??

I would guess most of us don't know much about a Glaston Sea Fury.??
My 89 after market ser. manual indicates the 225 as 81 only. RPM range as 5300-5800.You may be pressing things a little at 6,400.A 24 would put you at about 5,400,knock down your hole shot,and pick up your top end.
Any time you change props there are unknowns that make your results vary.
If your changing brands that introduces more variables.
Someone should be along with more specifics on your max rpm range.

 

[gsrsol84mm]

Re: 26mph with 19p ss prop@ 4200 - Is this OK ??

Thanks, I just realized the Merc is actually an 81 model. The top RPM may have just been around 6100 or 6200 rather than the 6400. I could not remember as my son was screaming for me to slow down. The 26mph at 4200 was right as we cruised at this speed for a while.
Maybe a 21 pitch prop would be the answer.
Thanks for any feedback.

 

[steelespike]

Re: 26mph with 19p ss prop@ 4200 - Is this OK ??

While any prop change can be a bit of a gamble.A 2" increase should drop your rpm about 400,slow hole shot a little and probably increase speed.Try to stick with stainless as changing material adds to the mystery.