Prop questions

I have a 2002 Yamaha F25 4 stroke on a 16 foot G3 jon boat. I just bought the motor back in March of 2016 and didn't run the motor that much over the summer. At the end of duck season I had the boat out loaded down with decoys and the motor seemed extremely sluggish at WOT. I was thinking a prop change might fix the issue. Yesterday I stopped in at a marine store and got to talking to one of the guys. He recommended dropping down to a 11 or 10 pitch prop. Today I went out and looked at my prop and it is a 10 1/2 pitch. So now I am not sure what to do. I was wondering if maybe a 4 blade prop would make a difference. Typically I do haul fairly heavy loads. Two or three guys plus decoys in the fall or coolers, rods, tackleboxes, jugs plus two or three guys throughout the spring and summer. I'm not looking to break any speed records I just want to be able to push the loads well. What do you guys recommend?

Yes a 4 blade will make a big difference in holeshot, and drivability. Merc has one that will fit, with the right hub. Spitfire 10p would be great.

In the Spitfire props you are to stay with same pitch as the 3 blade you have now. So if your rpms are good when boat is light. But low when heavy. Dropping that 1/2 pitch should be good.

I run one on my 60hp for river use. And SS 4 blade all other water. My rpms are the same as my 3 blade aluminum prop in the same pitch. But there's no blowout in tight turns, and holeshot is cut in half.


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Your hull is already a little on the heavy side for 25hp.

Add 2 or 3 more people in it, plus tackle, dogs, deke's, shells, whatever, and yeah it's going to be sluggish.

May consider going to a 9" 4 blade for running heavy loads, and keep your 10 1/2" for when you're running light. But there is no one-size-fits-all prop, so if you're heavy you will want to go back to the "small" prop, and when you're light, put the "bigger" one back on.

I don't care what prop manufacturers say, I've tested a few 4 blade props on my 2000 F25. I normally use an 11" SS Turbo Hotshot 3 blade. It runs at the top of the max RPM (near 6100, max is supposed to be 6000)-but I will be light going TO the hole, and a little heavier coming back with a cooler full of fish. I tried a Spitfire 4 blade 11" and it lost about 600 RPM and almost 4 mph. Went back to a 10" Spitfire 4 and got 500 of it back and a great holeshot. Keep in mind I don't usually run real heavy, just me in the boat and tackle and fish, and my hull isn't all that heavy either (1548). Tried a Solas 10" 4 blade and it lost a bunch of MPH and RPM even with the 10", the Solas blades are thick and create a lot of drag I guess. I would have been better with a 9" Solas than the 10" that I tried and didn't like.

I like a 4 blade but I just can't justify using one for what I do, and as far as I run. Once in a great while I will find myself wishing I had one back on it but not often enough to fork over the money. With your loading, you could use it better.

Is your G3 a regular riveted 1648? They are usually extremely light boats and only weigh around 300 lbs give or take a bit. I have a 1648 alumacraft that I had a 25hp 4 stroke suzuki on for a limited time and with 2 or 3 people it would fly. I had well over 1000 lbs of total weight in the boat and I used a solas 12 pitch aluminum prop. A 25hp should move that boat extremely well. Something is not right with that. A 10.5 pitch prop should be fine to move that engine. I now use a 20hp 4 stroke suzuki and my 1648 gets 25-27mph with near 1000 lbs of total weight and I use a 11 pitch aluminum prop on it. Something is definitely not right. My boat is rated up to a 35hp. If yours is like mine it should be the same,unless you have an all welded but even still a 25hp is way more than sufficient power to move that boat .