prop question

[skipe]

Hi everyone, I have a 1987 STV pro comp ski with a 1988 merc performace 2.4 EFI. It was doing 110 MPH at 8300 RPM. I switched props from a mazco re3 14.5x29 to a mazco re4 14.5x30. The rpm dropped to 6200 and the speed dropped to 65 to 70MPH. My question is could the prop change account for this much drop? I was told by John Mazar the drop would be 500RPM, which would bring me to my target of 7800RPM. Any help is appreciated. Thanks. Skip

[T-REX]

Juss kuz it'z a 2" differnce in pitch don't meen diddly!!!!........U kan go from one 28" masco to anuther 28" Mazco, and loose or gain several hunner rpm...Even stock out tha box, each prop iz differnt!!!....

Put ya 28 back on and make sure ya mota is still make'in HP, then U will know it wuz the prop!!!...

I had a 30merc cleaver that turned more rpm, than a 28merc cleaver!!!!....They wuz pozed to be "Out tha box" props!!!

[Mark75H]

I agree with Rex ... but my impression of a 40 mph speed change with that little of a pitch change .... damaged prop:(