Wrong prop for Rude

[V156]

I have 1991 16 ft Raycraft bass boat w/ a 1979 85 hp Rude on it. I took it out recently and noticed I could only get 4600-4700 at WOT. The motor has a 13X19 alum prop on it. The tach setting is right for the motor (6) and I've got her running smooth as silk. Max hp kicks in at 5000 rpm and I'm not sure if that's all she can take. I know some 70 hp Rudes turn close to 6000 but I don't know where my max is. I'm looking at another alum prop,I just need the right pitch.<br /><br />Dutch

 

[ob]

Re: Wrong prop for Rude

First off you need to make sure that prop pitch is your only problem in not achieving optimal RPMs at WOT.Other things to consider is motor height on transom,and fouled high speed circuit of carbs.<br /><br />You could try dropping back to a 17" pitch prop and water test to see if this puts your rpms in an acceptable window.Most shops will let you try different ones if you return them in new condition and are a serious buyer.

 

[seadiva]

Re: Wrong prop for Rude

SOUNDS LIKE ITS YOUR PITCH, THE HIGHER THE NUMBER THE LESS RPMS. HIGHER THE NUMBER THE MORE WATER YOU ARE PUSHING PER TURN. THE LOWER THE LESS WATER. A 17" SOUNDS LIKE THAT WOULD MAKE THE DIFFERENCE YOU WANT.

 

[Dhadley]

Re: Wrong prop for Rude

Something isnt right. A 19 on a 16' boat sounds like it should be about right. You are 1000 to 1200 rpm off. <br /><br />Have you checked timing? Are the carbs opening up all the way? Are you in reverse? (Sorry - couldnt help myself)<br /><br />Good luck!

 

[V156]

Re: Wrong prop for Rude

Thanks for all the replys guys. I'm getting ready to go to a wedding in N.C. so I've been running. No I'm not in reverse but I need to get the rpm's up. The boat plans very well (have a whale tail to help that). I've opened her up and trimmed her up so she's on the pad and 4600-4700 is all I get. I admit the prop has some dings in it but not enough to cause that big of a drop in rpms. My mech says it's in the right hole and the carbs open all the way. I do have a small problem with cranking her after sitting for a while(flooding if you don't do it just right so a car rebuild is probably in order) Would that stop me from getting the max rpm. The last thing I want is to keep lugging her and BOOM.<br /><br />Dutch

 

[V156]

Re: Wrong prop for Rude

Any ideas anyone?

 

[Dhadley]

Re: Wrong prop for Rude

Maybe theres somethings afoul with the tach going by what you describe. If the prop was big enough to hold the rpm's down that far, most likely the hole shot would be horrible but you say thats good.<br /><br />Make sure the tach is set on position 6 if its an OMC tach. <br /><br />Good luck!

 

[V156]

Re: Wrong prop for Rude

I'm positive the tach is set on 6. The question that really bugs me is should I go to a 17 or 15 pitch to get the rpms up. I'll double check the tach setting to be safe. Off to N.C. for the big wedding in Raleigh. Thanks for the replys.<br /><br />Dutch