CD19 prop Question

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Ericpg

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C Dory Year
2003
C Dory Model
19 Angler
Hi I have a 19' CD with a 2004 Suzuki DF70 outboard. It has a 13 1/4x 17 aluminum prop. I am only able to get 21mph in calm water at wot getting 4100 rpm. The motor seems to be mounted at the proper height. I have tried various trim settings with the engine and tabs. I read through the forum and think I need a 13 1/4 x 13. Just wanted to see what props others are using with this boat and engine combo. Or what prop your using with a 70hp motor.
 
I dont have the particulars but with a 13 1/2 x 15 on a df70 im doing much better than that. I have never run at wot but I recall get higher rpms & speed. If the water flattens out up here I will try it out & let you know vern C-Dog
 
I beleive if you go to a 13" prop you're likely to hit the rev limiter.

The DF70 has a very deep 2.42:1 gear ratio (think like a 4.11 rear end ratio in a truck) and with a flat prop like a 13" pitch I really think you're going to over-rev.

We usually use a 15" pitch prop on a Honda 75 which has a 2.33:1 ratio. Yes the Honda has a bit more horsepower (maybe) but it's also heavier and the Suzuki has a lot more mechanical advantage in swinging the prop and it's a smaller diameter.

I hope others with a DF70 chime in here but I'd be reluctant to try the 13" prop unless you can swap it after you try it.

Les
 
Ericpq,

When we bought C-Dancer, our 2005 22' Cruiser, we originally had a brand new Suzuki 70hp installed. Loved the fuel injected Suzi but we had a 15" pitch prop installed and we were definitely lugging, experiencing what you are now. Being new and waiting for the factory to send us a new prop, we were underpropped all of that first summer. Finally put a 13" pitch prop on the Suzi 70hp and the engine worked great, finally operating at the correct RPM's, It finally felt like a new motor should have felt. Alas, we moved up to the beefier Suzuki DF90 after the first season and haven't looked back. Knowing what I know now, I'm sure the DF70 would have been a great motor as well.

So to answer your questions, the 13 1/4 x 13 worked great on our 22' Cruiser. I don't know what effect it will have on your 19' Angler. Maybe you can go to a prop dealer who will let you use both the 15" and 13" pitched props for comparison?
 
I agree with Pete on C-Dancer. On a 22' the 13" pitch prop should work nicely but there's a lot of weight difference between the CD19 and a loaded CD22. Still the 13" prop might be the ticket which is really why you need to find a place that will let you try the 13 and 15 a figure out which is best.

Les
 
Thank you for the quick responses. I have a Solas 3 blade 13 3/4 x 13 on order. Will be heading to the lake for some calm water. If that doesn't work out I will order a 15 pitch.
 
i had a 15 inch pitch on my Yamaha 75 on my 19. I never got up to the wot numbers I should have even when empty. I think the smaller prop you're getting will be good. George
 
Theoretically the 5 " pitch difference should give you 1000 RPMs which is still in the lower part of the recommended ranger for that Suzuki . I think redline on that one [Suz. 70] is 5800 RPM . Ill bet on the 13" pitch !
I think engines are happier in the top 1/3 of the recommended RPM range .
Marc
 
Finally got out to the lake with my new 13 pitch prop lightly loaded I am now getting max 6k rpm at 27.8mph. Looks like I will be trying the 15 pitch next. After I ordered this prop a solas, I found a local company Piranha prop which sells a neat looking composite propeller with interchangeable blades. So I might go that route. I will post the results.
 
Most folks are disappointed with composite props . They break blades for no apparent reason and generally perform poorly compared to aluminum . 27.8 MPH lightly loaded with that prop sounds pretty good to me !
Marc
 
The composite is fine for a back up--but it has a lot of flex. You may want a 13 with more cup which will give a bit more speed and keep from hitting the rev limiter. I'll bet that the 15 will not get up to the 5800 you would like to see. There is a real art and science in getting the correct prop. Working with someone who will let you try several props is a real advantage.
 
Good points on the composite prop there is a lot of seaweed around here. I am going to leave the 13 on and run out in the ocean with a load of fuel and gear to see if I like it. Most of the time it is way to rough to get much past 13-15mph. With this prop that's around 4400 rpm. C-Dog what is your cruising rpm with that 15?
 
Now youve done it. Now im not too happy with my prop either. Went out today & put the pedal to the metal & the best rpm I could get was 4900 & the recomended operating rpm is 5200 to 5800. I usually cruise at about 3800 to 4000. Ill be waiting to see what you decide on for a prop. Vern / C-Dog
 
Ah! Now you've both done it! :)

So Ericpg is getting to 6,000 (and the rev limiter?) with a 13" prop and nordicstallion is getting to 4900 with a 15" prop. Both CD19's and both DF70s.

There's too much difference there to be prop alone so sounds to me like there's either a fair amount of weight difference or the boats are being trimmed differently.

Honestly, it sounds like NS could use a 13" prop and Ericpg a 15" prop. :) How much is shipping? ;)
 
yah you are right. Ericpg informed me that he was running with 18 gallons of gas where I was running with 48 gallons, salmon gear, bottom fishing gear, crab davit and power block and 80 to 85 lb deep cycle battery in the v birth, 9.9 high thrust kicker, 50-60 lbs misc. gear, two people. I guess I indeed need a 13" prop to use when the boat is heavily loaded. As I recall, the boat performed well with the 15" prop with far less weight aboard. Vern/C-Dog
 
I had a great day of fishing with the 13 pitch prop today. Weather was amazingly calm, lake Pacific. Still lightly loaded one tank topped off, kicker on the transom and some overnight gear. Cruised at 15-19mph 4400-4800 rpm. I am looking forward to testing with full fuel and more gear. So far I am happy with the performance. I am still searching for a 13 pitch with a little more bite maybe a different brand, to see if that would drop 200 rpm wot empty. I found a Suzuki SS 14 pitch that would be fun to try but at $390 it might have to wait. I sold my 17 so my excuse will be, I have to carry a spare. Thanks to all the helped with the decision.
 
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