copy and pasted from another fourm about the 2002 scr2800 single engine, two props

[jeff]

After playing around with different pitches & combinations, I found that a 22p for the fwd lh rotation larger prop, & a 20p for the rear rh rotation works the best for all applications.
24p was too high. The motor wouldn't spool up to operating rpm to get the boat on plane in a reasonable amount of time. 22p on frt & back was ok if it was just my wife & I & fuel. Once we brought guests & their luggage the boat was somewhat sluggish. The motor spins slightly faster at cruise now, but uses less effort & fuel to get on plane

is this true guys
what does he mean?

[shrew]

Hi Jeff,

Based on what i've seen with the 2800, I'd say "Yes, this sounds correct". I have a 24p 3 blade fwd and aft props and I think the boat is overpropped. I had a 7.4 crb and later repowered to an 8.1 MPI and still the boat is overpropped. I cannot get above 4100 rpm at WOT. The 8.1 should push 4400-4800. When I run the numbers through the Merc prop calculator for my boat, I get:

LH 15.75" 22.5p 4 blade
RH 14.25" 22.5p 4 blade

Oddly, the prop calculator is calling for 4 blade on both, but they only sell a 4 blade forward and a 3 blade aft, so that leaves me with some questions.

These guys are marketing a 4 x 4 setup which has had a few, yet promising write-ups:

http://www.hillmarine.net/Bravo-3-4-...4ds-hpr4cs.htm


I'm not completely clear on your question "What does this mean?" If you have a specific question, we can take a stab at it.

[Phillbo]

I have a buddy with a 2800 and the 7.4L that was a real dog with stock props. He went to Hill Marine and they set him up with a 4x4 set up that greatly improved the performance.

[M & M]

I was going to try this set-up since i have both 22p and 20p props, but was worried it mught cavitate, any thought?

[shrew]

Originally Posted by M & M

I was going to try this set-up since i have both 22p and 20p props, but was worried it mught cavitate, any thought?

Which setup? The Hillmarine 4 x 4 blade setup? Though I've never seen mixed pitch before. I would be sticking with the same pitch on each prop.