Overnighter repower new Suzuki 200 prop pitch

[mikesne]

Hi, I have a 204c that is at the dealer getting a new 200 Suzuki. The dealer messaged me earlier and said they were going to use a stainless 15.25x21 pitch. My (inexperienced) thoughts are that a 19P would be more accurate.

the old motor was a 175 2 Smoke with a 17P. I never could get the right rpm or speed at WOT. View attachment

looking for feedback, thanks in advance!

 

[DennisG01]

Provide your dealer with your results. Give them max RPM with a light to normal load when you have trimmed up as far as possible before ventilation or speed no longer increases.

Speaking of trimming - did you do that, similar to what I mentioned?

 

[mikesne]

I haven’t got it back yet. The first 10 yours is break in time and I can’t go to WOT until there’s about 5 hours on it. I’m just trying to save them the hassle and cost of changing out the prop if they get it wrong.

 

[DennisG01]

OK. Can you note your trimming and max RPM with the old engine. You only mentioned that you "couldn't get it right"... but I can't read your mind as to what that means

 

[mikesne]

OK. Can you note your trimming and max RPM with the old engine. You only mentioned that you "couldn't get it right"... but I can't read your mind as to what that means

the 175 had a 17p, I could only get about 5200 rpm’s at WOT. the fist prop I had on was a 19p and I couldn’t get to 5000 all the way trimmed up.

I really think that I had something going on with the motor. I now moved to a 200 4 stroke Suzuki. The dealer is installing a 21p. I know the gear set is different in the Suzuki’s so they might be on the correct path.

prior threads have suggested that the 19 was correct for the old motor. I’m just trying to avoid reproping after the new motor is broken i.

I also tried a 15p withe the 175, got on plane but lost tons of speed. No issues getting on plane with the 17 or 19.

 

[Sardinia306Canyon]

I guess you get the inline 4 cylinder Suzuki, DF200AP right? Not the DF200T V6.

The DF200AP has a gear reduction of 2.5:1 what is very high and allows the engine to turn a much bigger prop than other brands with their usual 1.75:1 gear ratio. Bigger Suzukis can usually swing a 2" bigger pitch and wider propellers (16 inch) than other brand installed before and in case of 2.5:1 also 4 inch more pitch.
Your dealer suggest a 15.25 inch wide propeller what i find a bit wired as afaik the correct prop for it'd gear ratio should be 16 inch wide and i am not sure why the suggest this one.
One reason to use smaller diameter is to reduce blade area on 4 blade props to keep similar pitch as a 3 blade but not bogging down the engine.
The other case may be that they want to rise pitch to make the boat hypothetically faster but have to lower diameter for the same reason above to reduce blade area.

Here a dealer install and tries props till he found the correct size and usually owner does not have to pay for that as dealers usually have a set of try propellers to dial them in and once right then the install the same, new one.

Chris