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The Proper wheel

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captlee

New member
I have a 1981, 25' 251 Catalina Express with a 305K (225hp) engine. The max speed I seem to be able to get from her is about 12.5knt/hr. On her 1" shaft, I have a 13x10 prop which seems to be what the engine spec calls for. But I keep thinking, I should be able to get more speed from her then that. Does anyone have a similar experience or is using a different size wheel? Thanks for any help / advice one might offer.
Capt. Lee
 
What RPM are you getting out of the engine when wide open? If you are hitting hte rated RPM (guessing about 4500 for that engine) then you need more prop (I'd try a 13x13)
("Wheel" is an old time term for prop.)
 
Lee, makes little difference as to Shaft Drive or I/O... Ford, Chrsyler or GM...... any WOT RPM test can only be accomplished after certain items meet criteria.

  • Hull clean and free from marine growth/scum/debris
  • Props in full tune, etc.
  • Ratio correct for the engine
  • Engine fuel delivery system in full working order (filters, anti-siphon valve, hoses, carburetor, F/I, etc.)
  • Engine in full tune and working order, of which MUST always include Ignition TAT..... (total advance timing)
Until these ducks are all in a row, a WOT RPM test to determine correct prop diameter/pitch, cannot be achieved.
Begin with these items, then move on to trying/testing props.

Point being.... don't get the cart ahead of the horse, or you'll just frustrate yourself. :)

.
 
1. do you have defective help?
2. Did they paint your props?

quit your stuck in the ball of brainless.
No one in your area has any idea what seamanship is.
 
Just to finish this thread, what I have done to fix this problem was to replace the 13x10 wheel (that may have been mis-marked and was actually a 12x10,) with a 14x8 and at WOT (which turns out to be 3950rpm - just as the chart in the manual indicates...) has doubled my speed through the water.
 
captlee said:
Just to finish this thread, what I have done to fix this problem was to replace the 13x10 wheel (that may have been mis-marked and was actually a 12x10,) with a 14x8 and at WOT (which turns out to be 3950rpm - just as the chart in the manual indicates...) has doubled my speed through the water.
Click to expand...
There ya go! :D
 
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