What propeller to use with CD-25 with 200HP In-line 4......?

[Avidmagnum12]

Hi John
Always appreciate your advise. I like to spend Joyce’s money on “shiny” things but I’ll play with the current one for now. I’ll need a flatter prop for Lake Powell in the future. It’s time to head north to cooler temperatures in Wisconsin and Michigan next week. Hope you are enjoying your retirement.

Tom

[Avidmagnum12]

I was able to pick up a like new SS Mercury Turbo 14 1/4 x 13P today. We will see how well it works in the next couple weeks and I’ll post results.

It’s shiny!.......Tom

[Avidmagnum12]

Here’s the report on my new “shiny “ prop. It has lots more acceleration out of the hole and mid range. Here’s the numbers I came up with on a similar day as my first prop tests.

5000rpm. 2.1 mpg. 22.5 mph
5200rpm. 1.7 25
5600. 1.7. 29
5800. 1.6. 32
6000 WOT. 1.6. 34.5mph

Soooooooooo.. The old prop went back on. I’m going to keep this one as a spare and for operations at high altitudes. The 13 3/4 x 17 is much more efficient on the C-Otter fuel wise.

The big thing I miss is the permatrim that was on my old engine. The Yamaha dealer told me that it would void my warranty. In 3 years I’ll be drilling holes and installing it on this engine for sure!

Thanks all. .. Tom

[smckean (Tosca)]

Interesting.

Clearly you are getting far more MPG from the 17"P prop because that prop runs the boat at far higher MPH at the same RPM. I did a quick calculation to see how the engine does in terms of GPH.....about what I would expect; namely, more GPH with the higher pitched prop, but not much different from the lower pitched prop.

I wonder how much strain the engine is under pushing that 17"P prop thru the water at those higher RPMs. I can tell you one thing, when I had a 17"P SS prop on my CD25 with the 200HP 4-stroke, the engine seemed to be working very hard (with the 17"P, I got very similar MPH as you are getting with your 17"P).

Do you have the numbers for the 13"P prop at lower RPMs......such as 3500, 4000, or 4500??

[Avidmagnum12]

As I’m learning there are a lot of factors involved in “proping” a boat. Props with the same diameter and pitch can perform differently. My boat does not have bottom paint, many 25’s do. My F-200 was installed with a wedge. The 17” on the C-Otter does not seem to be working to hard BUT ....I’m going to try a 15”P to see if better numbers are possible.

I do not have numbers at lower RPM’s with the 13P. I’ll play with it again in July when we go up to Lake Superior. Right now the boat is staying in the water at a marina. When we get to L’Anse we will put in daily and will play more with props.

I’ll post more numbers then......Tom

[Water Bill]

Tom,
Not sure if I gave you the info on the two props I have for my Yamaha 200 when we last talked. One is a Yamaha Reliance Series SS with14" pitch and 14 1/2" diameter and the other is a Solas New Saturn SS with 13" pitch and 15 5/8" diameter. When we meet up in L'Anse you are welcome to try them out on your boat to see how they perform.
Bill

[Avidmagnum12]

Thanks Bill
I’ll take you up on that. 👍
If you want to try one of mine, you’re welcome to put one on your boat.

See you soon.. Tom