Prop pitch and diameter

[odog110]

I just broke the original prop that came with my 1996 Mercury 90 hp. I bought a 13x19 prop thinking that’s what the original is but I must be wrong because the rpm’s are much higher than before and I lost some speed. The original prop doesn’t say anything about pitch or diameter it just says 48-77346-C1-19. When looking up those numbers online 13x19 comes up so that’s why I bought a 13x19 thinking it was correct. This is where I’m lost because the performance is different than the original. Maybe the original isn’t a 13x19?

 

[jimmbo]

Welcome to iboats

Is the replacement Prop the same Brand and Model/Lineage/Part #? 6 props, all 13 X 19, can provide 6 different Kinds of Outcomes. Blade shape, blade area, rake, cupping, will all play a factor.

 

[Scott Danforth]

welcome aboard.

I agree with above. unless you bought the exact 48-77346-C1-19 for the next prop, a generic 13x19p wont be the same prop.

 

[Texasmark]

13+ is the right diameter range for that lower unit which has a gear ratio of 2.33:1. A 19P on that engine on a light boat/light load isn't enough pitch regardless of how sophisticated the prop design. My 90, pictured in my Avatar was a SS Ballistic 13+ x 24 XP (added blade area) and it kissed 50 MPH at 56-5700 RPM with just me. Boat was a 17 1/2' Fishmaster by Taylor Craft, aluimum Bass Boat.

You didn't say anything about your WOT RPMs, GPS MPH, load, or boat size and type which would help us to help you.

 

[airshot]

If the new prop is an offbrand/ import prop, the numbers may not be very accurate.