Selecting the proper prop for your boat/engine..

I did a search on here to determine the correct prop for my boat/engine... I was unable to the answer I was looking for...So..... I am curious, is there a formula to determine the correct prop for your boat? My boat is a 16' Fisher flat bottom, it has a 76 evinrude 40HP, it does have a steering wheel, but no guages to determine speed or RPM's, with that said, I am unable to use some of the "formulas" I have on the internet... I do not wish to put any unneeded stress on my engine....

To piggyback that prior question...If anyone could assist me in determining the correct trolling motor for the job I would greatly appreciate it. Thank you..

Ok without an RPM reading you will never be able to get the correct prop. Your engine RPM spec is for 4500 rpm. I would worry a lot less about stress on your engine, and more about over rev...... Your boat seems fairly light for a 40hp motor so my guess is you are going to want to be in the higher pitch category for your engine.

There are many factors that go into finding out the correct prop for your setup. We simply need more info in order to help you. Like what do you have on there now?

My advice would be to buy a tiny tach and get an RPM reading if you want to be sure you are not damaging your engine.

Thanks...I'lll definitely look into getting a tach...will probably be asking for assistance on hooking up... Honestly, I dont know what the prop is... it was recently powder coated by the guy I bought the boat from.. I will look for markings on it when I get home... he had two props for it, said one was a speed and one was a "torque" prop for pulling people... As I have said in my other posts, I am a boating virgin and don't really know what is what yet. Thank you again.

No problem, we will gladly help you with all of this and get you dialed in There are usually stamped markings on the outside of the prop between the blades and then a second set on the hub itself behind the prop nut. Will read 12.5X13 or something similar most likely for your motor. Get those numbers and a tach and we will get you set right.