Been considering trying a big blade chopper on my Rally Sport 21 300 ProMax. Standard small shaft unit. My concerns are will the 300 likely break a blade, possibly breaking the shaft? Anyone run a chopper on a 300?
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Been considering trying a big blade chopper on my Rally Sport 21 300 ProMax. Standard small shaft unit. My concerns are will the 300 likely break a blade, possibly breaking the shaft? Anyone run a chopper on a 300?
interesting question, Mercury recommends a cleaver for the 300 hp. Mazco says (web site , looking at a 3 and 4 blade chopper) "The blades are thinned for ultimate speed, but yet thick enough for durability and are able to withstand the torque of the highest horsepower outboards." Looks like Hill Marine has choppers under 300 hp and cleavers over 300 hp. Good luck. breaking a blade at 5000 plus rpms sounds scary.Quote:
Originally Posted by 99fxst99
We threw some blades at WOT on the 300PM... 4 out of 5 grenaded the brand new sportmasters and sent everything to the bottom of the lake.
That's all I need to hear. Pretty much what I thought. I guess it goes on the shelf for now.Quote:
Originally Posted by David - WI
Best prop would be a Hoss HPD in a 28,29 or 30. Strong and great blade shape for take off, lift and top end. One of my best props for my 22' activator and 21' superboat with 300 merc.
Best to convert to fat shaft however for strength as pressure on standard shaft get too high when running blades high out of water at top end.
Another top prop I will say best to try in standard shaft is a Spinelli DR4 29 with a touch extra cup by Tim Hoss. Was my fastest and good weight carry at high engine heights.