Right now I am running a 14x21 pitch Suzuki propeller on my 165cs navigator. It hits about 5600 rpms WOT around 38-40mph GPS. Motor is on center hole (5 holes). As I can tell I'm just a little over RPms. I'd like to go Stainless and I do like the Suzuki props.....so 14x20 or 14x22. I am sure I can raise the motor up a hole or even 2 at this point. I can trim it way up before the I start losing speed. Any thoughts??? Anyone else with this motor on there 165cs nav?

which navigator hull is it, the narrow one, or the new wider one (07 or later I believe). I'm running a 90 honda on the new 165cs hull (92" beam). But, I think your gear ratio is much lower than mine, plus by your rpms, I'm guessing you have a 2 stroke. If you do have a four stroke, you may want to reconsider going stainless. I love the performance from my current prop, but the 4 stroke rattle with it is rather annoying. Thinking of trying another aluminum prop, with a slightly higher pitch for coooler weather, and to get rid of that rattle.

Is that RPM with just you and a light load of fuel and gear? If so, I think you should drop to the 20 pitch. If you're hitting 5600 RPM during the heavy air of summer and a full load of fuel, you could probably get away with the 22 pitch and end up around 5200 RPM at WOT. However, keep in mind, you'll lose some hole shot and your motor may lug with two or more passengers aboard. I would not advise raising the motor any more but I guess it depends most on where your cavitation plate currently lines up with the bottom of the hull. How many inches above is it?

The motor is a 4stroke suzuki, rattle what rattle??? it is so quiet!! The boat is the wide version. This thing pulls 5500-5600 no matter what it seems, 2 labs, wife and I and still 5600.

put a stainless prop on it, and you'll hear it. When idling in gear. it's the nature of four strokes. Likely never hear it with aluminum, but the extra rotating mass of a stainless prop makes it much more annoying.

If your max rating is 5500, you definately don't want to drop, since you're over revving already. If you do go stainless with more cup, aim for the same pitch, or perhaps 1 inch steeper like a 22.

Stripe, you may want to take your motor to a mechanic and get the valves checked. I've got a Suzuki Four Stroke and have no problem with any rattling noise with a stainless prop.

2catch, going with an equal pitch stainless prop with any kind of cupping, like the Suzuki prop you're considering, is going to reduce your RPM's by approximately 200. However, you will see more speed with the equal pitch prop due to the better bow lift a cupped stainless prop provides and less flex.

Now if the RPM's numbers you provided previoulsy were attained with a full tank of fuel and/or with another person on board, then you should consider increased pitch.

I know it's a different boat completely, but I had to jump to a 22" stainless on my 618 Ranger Tiller - still got max R's around 5500. I'd give that prop a try . . .

What did you have before that and what were the rpms?

I had a 21" SS and with me in the boat I'd go over max R's, so I stepped up to a 22" which still had no problem getting me on plane with two other guys in the boat.

Stripe, you may want to take your motor to a mechanic and get the valves checked. I've got a Suzuki Four Stroke and have no problem with any rattling noise with a stainless prop.


no, nothing to do with valves. perhaps suzukis are timed differently and don't get it. or, you may only notice it if it's running on muffs. it's explained very well in this post from another person on another board:

ok. ill try simple physics once more, on a 4 cylinder 4 stroke yamaha 1 and 4 move up and down together as do 2 and 3. when one is compressing gas before fireing it tends to slow the crankshaft as 4 has an open exuast valve and 2 has an open intake and 3 is almost at the bottom of its power stroke., if the crank slows, the driveshaft slows, heavy prop is under no such slowdown and rotates the clutchdog teeth,splined to the propshaft, slightly ahead of the dog on the mating gear, now, WHHHOOOOOSHHH bang, cylinder one fires, the crank rapidly accelerates, now the drive shaft speed is faster than the now slowing propshaft, whack, the dogs hit again. process repeats when number 3 is on its way up, then 4 then 2 then 1 then 3 then 4 and so on and so on. the flywheel helps but can only be made so heavy .take the prop off and the noise disapears, ya outta hear some of the V76 motors that only run on 5 cylinders idle on the muffs with a 15X19 wheel.
so yes on certain engines, especially 4 strokes as power impulses occur every other time the piston comes up, some rattle in gear out of the water is normal.

anyone got a 21 or 22 stainless they'd like to sell???

Not sure where you are located but I have an extra 14 X 20 Suzuki prop if you want to give it a try. I'm in the Twin Cites area if your close. I think you will see close to the same RPM's going down to a 20 SS as compared to a 21 Aluminum.