Correct prop

[Mugsaway]

I have an '09 Suzuki 140 4 stroke. I recently squared up on a rock on Mille Lacs and had a new lower unit put on. The mechanic asked me at what my RPM's are at WOT. I told him I had now idea - still in the break in period. He asked how I thought the boat came out of the hole and I told him not as quick as I thought it should.

Sooooo, he told me he would put a pitch of 21 on instead of the 22. I went out today and noticed the boat was a little quicker out of the hole and at WOT I was at 6100 RPM's.

My question: Should the motor be at 6100 RPM's at WOT? The mechanic said the sweet spot is around 5850 RPM's (?). Do I need a different prop pitch? Or does this sound OK?

Thanks,

Mugs

[TR21]

6100 is a bit high for that motor. If you are going to stay with that prop I would trim down a bit and try to keep it around 5800-5900. At 6100 were you trimmed out? Did you feel any walking at all ? Did you have any throttle left? What kind of prop is it? Just checked the Suzuki HSOforum and 6200 is the max for that motor. In fact the operating range is 5600-6200. So I guess if you want to run at the top it should be allright.

[Mugsaway]

At 6100 were you trimmed out? Yes

Did you feel any walking at all? No

Did you have any throttle left? No

What kind of prop is it? Brand, I don't know. It is aluminum

If I went to another pitch, would it run lower RPM's and still get the same speed out of it? 6100 is still in the operating range, however I don't know if I really want to be running that high. Will it eventually ruin the motor? At what speed would you run this motor at?

I appreciate the responses,

[sparkyaber]

One other question is load, Were you fully geared up, average weight in boat, or very light. If you were light, you will definatly be alright. If the operating range for the suzuki is 6200 rpm's, then you would be right in the sweet spot. Generally higher pitch equals more speed slower to plane out. What type of boat is it? That is also a big factor. If you start playing around trying to find the best performing prop you would be wasting your time messing with aluminum. Save some time and swith now to stainless. Also, your dealer should let you try every prop in the dealership as long as you buy one from them. My last boat I tried like six before I found the one that worked the best. My current boat works great with the prop that came on it. If it helps, I have a reata with a 175 suzuki being pushed by a 25 p rev 4 (I know a Merc prop on a suzuki?) with all of the pvs holes plugged.

Hope this helped.

[SkunkedAgain]

I just bought an '09 Suzuki and it tells you right in the owner's manual about correct operating ranges for the motor. I wouldn't worry about it running at the high end of the rpm range, as long as it stays within that range.

[marine_man]

I think you're just fine where you're at, and would prefer to run in the upper end of the RPM band, so you're in good shape.

marine_man