Prop question

I have a 1989 Johnson 50Hp Two Stroke Outboard. Does anyone know what propeller I need for a replacement? My current propeller is in need of replacement. Is there a big difference on pitch sizes? How does this affect the boat? Is there a standard spline count? If anyone can enlighten me I would be greatful, thank you.

Ok first off YES pitch selection is very important. For every inch in pitch you change your RPM's will go up or down about 200 depending on which direction you go. And staying within your engines RPM range is very important for you engines health and performance.

Now, do you have the diameter and pitch of old prop? Do you know what RPM you were running?

Your motor has a 13 spline shaft, your recommended RPM range is 4500-5500. Ideally you want to be on the top end of RPM range to get best performance. We would need far more info to help guide you on buying the best prop. That motor can run anything from a 9 pitch to a 17 pitch depending on size and setup of boat.

I believe the 1989 50hp came from factory with an 11.75 X 17 aluminum prop. That doesn't mean I am telling you to put that on your motor though....just a reference of what they came with. Each boat and setup may require different prop size as stated above.

Thank you, the boat is a Bass Tracker TX17 Tournament. I have not run it yet. Picked it up in October of last year, I was finishing building my house so I could not put it in. The current prop on it is all chewed up on the edges, need to put something on it before it goes in this year. This is my first boat, so sorry if I am phishing for info due to my ignorance but I am just inexpirenced. Thanks for the help, any more would be much appreciated.

Find out what size prop you have, it should have a stamp on the prop saying the size.....something like I posted above 11.75X17. Props usually have one stamp between the base of the blades and another on the back of hub where your prop nut is. Also post a pic of your prop, just because it has some dings does not mean you have to put a new one on, you can file down the dings with hand file or grinder.

I also have a 1990 50hp Johnson 2 stroke 2 cylinder. Mine tachs out at 4500 rpm and the prop is missing a little on the edges. I was contemplating getting a new one. The only marking i could find on the outside of the prop says 15