[dieselwiezil]

[An update for me: Went out last weekend Top speed is 44mph and 3850-3950 RPMS. Trim indicator is half way or a little higher than half. This data is collected JUST before Cavitation begins. I guess im going to do a tuneup. It is QUITE possible all my stuff is OEM from the factory, and being 8 yrs old, it needs to be changed. It has 97 hours now. Another thing I am thinking about is that if the throttle cable may be stretched? I have seen them do it on construction equipment, so Im going to check that out too.

I cannot find my thread I had a couple weeks ago, and Im not tryin to hi-jack this one.[/QUOTE]

I just checked my throttle cable and there is NO WAY that this could be my problem. At the High Idle stop on the carb I still have almost 2in. of throw in the cable. Maybe it needs to be tuned a little richer? Im at sea level, and theres no sign of over fueling in the carb. Maybe it needs to me turned up a little bit. Any other ideas on performance.

[z275st]

dieselwiezil,
Have you been able to try a 19p prop. It should get you in the RPM range you need to get the horse power to gain speed. With a 23" four blade I was at 4650RPM and 50mph. A change to a 21" four blade and I got 5000RPM and 53mph.

[dieselwiezil]

well im planning on doing a tuneup this weekend. Im going go out again to see if that made a difference. Then I will check out the prop. How do you measure the diameter of the prop? I measured from the hub shell to the tip of the blade and its roughly 5in. The hub case is 5in. Does this mean my prop diameter is 15in?

[z275st]

Yes, its the center of the hub to the tip of a blade X2.
Good luck!