Hey guys,

I've googled for a few hours and not sure I'm getting the right info.
I thought I would check with the real experts, here. Often times I get what I feel is better info ,faster, but I hate to bother everyone ,too much.

I have a Mercury 60 hp on my bass buggy pontoon. It is not the original motor.
according to Suntracker, my year could accept up to a 70HP

I am looking to get a new prop, and keep the old as a spare. On the side it says 48 73132A40 10P.
The info I have found is that it is an original prop, but Mercury #'s are a little tough to decipher.
I'm guessing it's a 10 pitch, and on a prop calculator site , that I found, it recommended a 12 pitch , based on the info I entered, which I feel was pretty accurate.
Just about everything I read , said to beware of changing the pitch too much, but couldn't find out ,how much is ,too much
I was able to find out that it is allegedly 11 1/4 inch diameter,( I will actually measure it before I buy.) The calculator site recommended 14 inch, which seems quite a bit larger
I will probably hit up the local boat repair places also, just wanted to see if anyone had any advice.
I keep googling and finding more info , and more questions, and less answers, so I am going to post this for now.

Thanks for any info.

You can change pitches for the performance you want. Power and hole shot or higher top end or a pitch in the middle to compromise. Each change will effect top end speed and rpm so you have to be mindful of that and watch your tac so you don't red line the engine at or before wide open throttle. The outboard tech at the shop will help you.

I have a merc 60hp fourstroke on my bass tracker. It lacked power to get up on plane fully loaded so I got a four blade spitfire prop. I lost a little on top end but it planes fast now. The dealer should be able to tell you if one would work for you if that is the issue you are having.

What RPMs are you getting with the old prop? at wide open you should be just under the max rpm for that motor, around 5500 rpms. Every inch difference in pitch will be about 150/200 rpms.

Going to the dealer will only give you an educated guess, which you already have. The only way to know what you need is to tach out the boat/engine with your normal load and the prop you have, Too few rpms drop the pitch, too much add to the pitch.

How does it perform with the 10 pitch? If you are happy with the performance stay with that pitch. If you want more top end go to a higher # . The lower #'s get you out of the hole and up on plane quicker while the higher #'s will get you a little more top end but not so quick out of the hole and a little slower to get up on plane.

^^^This^^^

Some local prop shops will let you change out props if you don't booger them up. That's the best way if you can swing it.
Gotta have a tachometer. If you don't have a built in tach on your boat there are small relatively inexpensive ones that can be purchased from Amazon. Under 25 bucks as I remember. They work well for what you want to do.

I was always told it's better to over rev you boat engine than to under rev it (too much load).
That way, with no load the boat is over reving a bit but with your boat loaded the rpm will drop and get back down to it's proper operating rpm.
Too much load is hard on rod journals and can burn holes in the top of pistons.

thanks for he info everyone, I am happy with the performance of the boat ,as is,however the prop that is on it has always been a little beat up,
I suppose it has seen the bottom of the Mississippi , once or twice. I just bought it last fall.
I just figured, maybe a new one would be a little better., and then carry the old as a spare ,just in case.
It does not seem to be unbalanced or anything, I have not noticed any vibration, it's just nicked up a little.
Once again, thanks for the info, everyone, I knew I could count on the TMan family to start me in the right direction.

There is a place in Plymouth MN called Prop MD. I’ve used the guy for 20 plus years. He rebuilds props and handles some new brands.
Far and away the most knowledgeable people I’ve ever known on the subject, his business has blossomed because of it. They are truly experts and a simple call to them will get you fixed up, they are happy to share info.

Have all the pertinent info at hand as they will ask. Size of pontoon, size of pontoons themselves, motor specifics etc.

Osky