Please help me better understand boat motor props.

[mr_jman]

I hit a rock and took out about half of one of the blades on my prop. I have a 1977 Evinrude 35HP and the current prop is a three blade 10x15. Here are my questions though...

First off, is it safe to run the motor in this condition or will I wreck something else by running it with half of one blade broken off?

If I should be looking for a replacement, how interchangeable are prop sizes?

Do I need to make sure I have a size 10 diameter prop and just adjust the pitch if I want to?

Or does a size 9 or 11, etc. diameter prop work as well?

My current prop does a fair job with planing out my boat, but if I went with something else, should I increase or decrease the pitch to get on plane quicker?

I won't be going with the stainless or a 4 blade version most likely. Just looking for a "cheap" replacement prop.

Thanks for your help in advance!

[wakeguy]

You have two primary risks with running your current prop. One- over reving the engine. Two- long term the vibration can take out a prop shaft seal allowing water into your gearcase. You can have your current prop rebuilt or you can replace it. Ideally you want a pitch that will allow your engine to get near the maximum recommended rpms with a typical load. This will give you the best all around performance. If you went with a lower pitch like a 13 you will get better holeshot but you will also increase the rpms at wide open throttle. If you don't have a tach you should stick with the same pitch. As long as you buy a prop designed for your engine you don't need to worry about diameter. Diameters may vary a little bit based on prop shape.

[Ufatz]

Make your life more simple. Take your old prop to the prop shop and tell them you want a new one. Since you state your boat runs fine and at a reasonable speed why complicate things by chasing after a new pitch, new diameter etc.etc.

Make life simple.

But DO NOT run the engine with the present prop.

[mr_jman]

I found my exact prop on "thE bay" for about $50. Is this cheaper then repairing mine? I could always repair the one I have for a replacement and buy a second as well.

[delcecchi]

The 50 bucks is no more than the cost of repairing your old prop, although it varies some depending on where you are. I paid 60 for a repair last summer.