Prop Size Question

[geoffreykwright]

Hi. I have a Catalina 34 MK II (Year 2000 - Hull 1494). The previous owner put on an after-market Gori folding 3-blade prop (15"x9" RH - Reduction ratio 1.88:1).
A diesel mechanic was checking out my engine and says the engine is very healthy but he can't figure why I cant get the RPM's more than 2000. He is wondering if the prop is too big for the Universal M-35 engine I have. When cruising I can't get more than 1500 rpm out of it.

My question is does any one know the specs for the factory prop from Catalina? Has anyone else had this problem?

Thanks in advance.

 

[Stu Jackson]

Geoffrey,

You might want to ask here:

http://c34.org/bbs/index.php/board,11.0.html

With your C34, you'll find many boat-specific answers. You're welcome to join us there.

 

[Claygr]

You could check with Gori to see what they recommend. It also is possible that your tachometer could be off but that seems like a big deviation.

 

[Claygr]

Sorry, I thought of one more thing - you can't compare the pitch of a fixed prop with a folding/feathering prop or between different manufacturers of folding/feathering props. Catalina may specify a 15x9 three blade fixed prop but that does not mean that a Gori (or Flexofold or Variprop, etc.) 15x10 prop is wrong for your boat/engine. What would be helpful for you to know is the pitch for that model of Gori prop on a C34 with the M35 engine.