help required for prop size

warnie100

Cadet
Joined
Apr 11, 2010
Messages
6
hello folks i am a newby here and have just purchased a 1980s marine craft 4.5 mtr runabout which has a 1979 70hp evinrude on it .it has a 13.4 15p on the boat but the top speed id quiet slow it doesnt have a taco or speedo so its hard to tell i tried a 17p and that seems better would a 19 be better and still get the correct shot out of the hole any help is appreciated
regards warnie100: :confused:
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: help required for prop size

Welcome, please read the stickies at the top of the page and the helps on the prop store page.
You really need a tach and speedo or gps to do a prop change.
Your motor needs to be able to operate within its rated rpm range.
If it forced to operate below its rated rpm you will have poor performance and it may cause premature motor repair problems.If operated above its rated rpm could cause premature motor failure.Before making any prop selection we need the details of your present setup.You may need something other than a prop change.
A tiny tach is about $40 and easy to install.Perhaps you can borrow a gps.
 

warnie100

Cadet
Joined
Apr 11, 2010
Messages
6
Re: help required for prop size

thankyou for that i will geta small tacho and see whats going on regards warnie
 
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