Correct Rpms to prop Size. Albin 28 te Flush Deck

[dasabalon]

I know this has been discussed. I have not been able to find an answer that fits my need.
I own a 2005 flush deck. Hurth gear 2-1 ratio. 19x17.75 5cup 4 bladed prop. I am trying to get the 3900 wot rpms that is recommended. I can get 3750 22knots. 3220 17.5 knots.. Ive tried the miriacle prop by Acme 18x17 5 cup same results as my old 4 blade. I have an aetna tach and Ive used a photo tached while I was running. All readings are spot on.. My old Beade tach was 300 rpms off, giving my wot at 4050 rpms.... I just had the Prop shop repitch my old wheel to 19x16.9 to get the wot rpms needed so as not to overload the engine... This was a total failure. I got 10 rpms more 3760...
Ive read Marks testimony "Serenity"to to the Acme Prop. The 3 Blade for me was a failure they then sent me a 4 blade 20x17 worked just like the 4 blade teignbridge I have on now... totally not worth the 1600.00 price tag.
I am lookinmg for someone with the same set up.... Does anyone get the correct Rpms and is Certain ther tach is on and if so what size prop are you using

[RobS]

Have you checked no load rpms?
Should be +/- 4,200

[Tree]

Each boat can be different. I originally swung a 19 X 19 5 cup. I'm now swinging a 20.5 X 19 3 cup and as a result gained 2 knots wot and 1.5 knots cruising speed. My Tach is showing off by 50 rpm and I've not had a chance to photo tach the engine yet to confirm I am getting full rpm but tach was the same before and after changing the prop.

[catalina_mike]

My issue originally was actually the throttle was not going to full on the engine and needed resetting up. Mine was mechanical linkage not a prop issue.

[dasabalon]

At WOT Under no load I get 4135

[dasabalon]

Could the turbo effect the top end under load?

[RobS]

Normally any turbos issues reveal themselves as black smoke. Here's some reading that covers a broad spectrum of things. Did you check the linkage as Mike noted?

http://www.sbmar.com/articles/understan ... eshooting/

[socalmike]

My issue originally was actually the throttle was not going to full on the engine and needed resetting up. Mine was mechanical linkage not a prop issue.

Mike. Can you go into a little detail on this. Thanks.

[RobS]

here's a photo, Mike can explain what he did.

[catalina_mike]

The mechanic popped off one of the lower linkage connections and had me advance the throttle at the helm to full. When the ball was compared to the throttle lever on the engine the engine one would have more room for movement to max. The connector for the cable on the engine for the helm leaver was adjusted to allow full throttle. Then the minimum was checked and it was fine. I'm not at the boat to take pictures of the adjustment but it was right on top as I remember.

[socalmike]

Thanks.