Prop recommendation for TC255 w/Suzuki 175X2

Those of us who run the 150 Suzuki use the 16 x 21. I am not sure how much faster you will go with the 175----perhaps fully loaded a few miles per hour--and that might be nicer. But I find that I cruise most of the time at 25 mph--and occasionally go to 35mph cruisng speed. The boat is capable, fully loaded of over 40 mph--not often I need to do that. The 175 will give you the extra HP at the higher RPM--and that equates to running in the over 38 mph speed range.
 
thataway":x9j4setr said:
Those of us who run the 150 Suzuki use the 16 x 21. I am not sure how much faster you will go with the 175----perhaps fully loaded a few miles per hour--and that might be nicer. But I find that I cruise most of the time at 25 mph--and occasionally go to 35mph cruisng speed. The boat is capable, fully loaded of over 40 mph--not often I need to do that. The 175 will give you the extra HP at the higher RPM--and that equates to running in the over 38 mph speed range.
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Bob,

No, I don't think I'll be running at WOT very often and I would like to be very efficient at 25-35mph. Since I don't think I'll lack for power, what about a bigger prop?
 
You might run it by Ken at propgods.com, he runs a forum and the advice he gave us for propping our CD 25 with its Suzuki 200 was spot on.
By the way (ok I know its blasphemy) Eds Marine superstore has good pricing on Suzuki SS props with free shipping to the lower 48 states. Just be sure you order the right one or pair in your case as there are no returns.

Eric
 
The Suzuki 16X 21.5 is your prop . It works for both the 150s and 175s as the rpms increase slightly with the increased redline of the 175s
The 16" diameter Suzuki props come in 1.5" pitch increments starting at 17P. No need to obsess on this as we have rigged a number of them and the performance is awesome with both motor choices.
Marc
 
No, I don't think I'll be running at WOT very often and I would like to be very efficient at 25-35mph. Since I don't think I'll lack for power, what about a bigger prop?
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Thanks Mark--it is the 21.5 prop. No the larger pitch prop will lug your engine at the lower speeds. I don't have my RPM vs speed table right in front of me, but the revs are surprisingly low for the cruising speed on a plane at 25 knots---and that is why the boat gets good economy. With a larger prop pitch, you will not only be slower getting on a plane, but will have less HP and torque at the cruising speed. I suspect that you will have a significant increase in prop slippage also. All of these will equate to less effeciency. The increased HP is only at the high end of the revs of the 175 over the 150--at cruising speed, they will produce the same HP and torque.
 
Thanks for all the help. What do you make of these?

Suzuki_175_torque.gifSuzuki_175_torque2.gif

Ben at Master Marine did say that they tried 16X23's on a Sea Sport with the 175's and the owner thought it was too much prop.
 

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One of the biggest problems with outboard manufactuers is that they don't give actual HP and torque curves--as all of the diesel and many inboard gas engine companies do.

Without numbers on such a graph--they are almost meaningless. often they take the mid part of a graph--and blow it up. You want to know how many foot lbs and at what RPM.

There is no question that you will go faster with the 175's. The Props which Marc put on my Tom Cat--and it was early in the evolution--were perfect. Good speed, good lift, good time to plane, and good fuel economy with reaching WOT, even with a full load.

Will you go any faster at 3200 RPM? I don't know--but that is a good cruising speed. Remember that you only get 200 RPM change for a change of 1" of prop pitch.

Would I buy 175's--probably yes over the 150's. But it would depend on the cost differential. When I ordered my boat the rated HP was 300. Since then folks have been putting bigger engines on the boats. I am happy with the 150's.
 
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