Hi,
I am replacing a broken prop on my boat. I have read about choosing the correct pitch size (RPM at WOT test) and I will eventually do that test (when I will get some new prop to put on). But what about the correct prop diameter? Is there a rule for choosing the prop diameter? This boat was purchased used and there is no guarantee that the prop size was optimal (although it was OK I think).
My older prop was 14.25 inch (see below) and there was still some space between the blade and the lower cavitation plate - about 1? or so, if I remember it right. Was this just OK, too much, or too little?
Can I go plus/minus half inch or so with the diameter of the new prop?? Let us say 13-3/8? Or 14-3/8?
Is there a rule about how much space must be there between the blade of the prop and the plate of the outdrive??
Another question: I want to buy a used stainless steel prop. If the diameter and the pitch value match what I need, does it matter what engine this prop was originally intended for?? For example, can I put a Mercury prop (outboard) onto an I/O Mercruizer?? Or, an OMC or Volvo prop onto a Mercruiser?
Info:
- Performance issue: broken prop.
- Current prop: Qicksilver 14.25 in, 21 pitch, aluminum.
- WOT RPM: did not try to measure when the prop was good, but will do with the new prop.
- Engine: Mercruiser 4.3L, 1993, Alpha One Gen 2.
- Boat: Searay 20 feet, 1993, open bow, average fiberglass set up, four people average load.
Thanks for your feedback!
I am replacing a broken prop on my boat. I have read about choosing the correct pitch size (RPM at WOT test) and I will eventually do that test (when I will get some new prop to put on). But what about the correct prop diameter? Is there a rule for choosing the prop diameter? This boat was purchased used and there is no guarantee that the prop size was optimal (although it was OK I think).
My older prop was 14.25 inch (see below) and there was still some space between the blade and the lower cavitation plate - about 1? or so, if I remember it right. Was this just OK, too much, or too little?
Can I go plus/minus half inch or so with the diameter of the new prop?? Let us say 13-3/8? Or 14-3/8?
Is there a rule about how much space must be there between the blade of the prop and the plate of the outdrive??
Another question: I want to buy a used stainless steel prop. If the diameter and the pitch value match what I need, does it matter what engine this prop was originally intended for?? For example, can I put a Mercury prop (outboard) onto an I/O Mercruizer?? Or, an OMC or Volvo prop onto a Mercruiser?
Info:
- Performance issue: broken prop.
- Current prop: Qicksilver 14.25 in, 21 pitch, aluminum.
- WOT RPM: did not try to measure when the prop was good, but will do with the new prop.
- Engine: Mercruiser 4.3L, 1993, Alpha One Gen 2.
- Boat: Searay 20 feet, 1993, open bow, average fiberglass set up, four people average load.
Thanks for your feedback!
