Prop problem

gustafsonerik

Petty Officer 1st Class
Joined
Jun 25, 2006
Messages
238
Hey guys..I have a merc 65hp 1970 4 cylinder that i inherited..it doesn't have a prop on it..how do i know which one i need? when you say "count the splines" do you mean the teath on the spindle or the grooves my serial number is 287411 if that would help thanks Erik
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Prop problem

Finding the prop that fits is just one part of the equation and that's the easy part. Determining the "type" of prop you want is quite another bag of worms. There is aluminum, stainless steel, three blade and four blade and then each of those has a wide range of "pitch" to select from. Since we have no idea what boat this engine will be installed on, we don't have a clue what to recommend (at least I don't). When selecting a prop, you want to pick one that allows the engine to rev at the top of its recommended RPM band at wide open throttle with a normal load. Selecting a prop with too much pitch causes the engine to lug. Too little pitch causes it to over rev. Let us know what boat you have and we might be able to get you in the ball park.
 
Top