Help with Prop Trouble

[skibo84]

I have a '88 Rinker 18' with 4.3 L Mercruiser and Alpha 1 drive...I currently have a dinged up 19" SS prop on it and it is over-reving. WOT RPM should be around 4200-4800, but at WOT it appears to be closer to 5250 now @ around 40 mph, I think speedo is messing up at times though. If just purchased a 19" aluminum prop because I want the hole-shot for skiing but I do want to fix the RPM range at WOT. Did I get the right prop or should I have went ahead and moved up to the 21"?

 

[steelespike]

Re: Help with Prop Trouble

When going from SS to Al all bets are off.With a dinged up prop even harder to do.Assuming the SS 19 was close to normal the Al 19 may actually turn more rpm.It could also turn less because it doesn't lift the boat like a stainless can.But again when going to a different material there are more variables.The 19 should work ok but you
may have to watch the rpm.A 21 would make hole shot worse.
You can get your stainless repaired It should perform better than the Aluminum.