prop pitch difference

RRRKKK

Cadet
Joined
Dec 6, 2003
Messages
24
I am currently running a 13 1/2 18P 3 blade s/s prop on my jon boat with a fresh rebuild on a 1991 60hp Johnson wot is 6000rpm with a trim out of almost 6400 rpm. "runs Good" I have a chance to buy a 12 3/4 19p 4bade s/s Spinelli bros prop any idea what the rpm bifference or performance will be.<br />Dhadley glad to hear your are ok and I think I still might need to raise the motor<br />Ron K
 

walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: prop pitch difference

I don't know how the Spinelli will compare to the Raker, but to gues at it, I'd say the r's would drop "slightly", but that may change considerably if you can still raise the engine some, and I would recommend you try that first, then look into some props or possibly working the Raker.....adding bite to a prop vs. removing it will generally increase efficiency.<br /><br />EDIT: One item that becomes more clear to me every day is that any given prop can perform in such a wide array of levels, that it is really tough to tell just what that prop will do without being able to test it. Recommendations are going to be real close from guys like Dhadley, and he's had experience with about any prop made, but there are some variables that are just plain tough to guess vs. factual numbers of testing.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: prop pitch difference

Generally Spinellis are very very good. I'd sure try it if I had the chance. They usually "bite" hard so you may drop more rpm than you think but it should run faster. And probably quicker too. In spite of the smaller diameter. One thing to watch out for with ANY used prop -- if its been reworked you never know what youre getting. If it doesnt work out dont judge all of the brand by that one. <br /><br />Anytime you try to compare brands it gets a bit touchy. Sometimes its hard to compare a Stiletto to a Turbo even though they're made by the same folks.<br /><br />Kenny's right about the testing. You can try a prop on 6 different hulls and 1 will always react better. Ah, testing -- a great excuse, I mean reason, to go boating!
 
Top