Fast, fast really too fast

[CnC for me]

Hello all,

Interesting bit of oddness that I would welcome input and suggestions on

When cruising at higher RPM (no tach yet) close to hull speed, (5.8-6.0 kts by gps), we will get an occasional racing of the A4. Seems like a loss of power but haven't waited too long to throttle back. After throttling down, things settle back in and behave normally but often reoccur.
Fix at this point has been to simply cruise at slightly lower speed (5.0-5.5 kts) which seems to prevent it.

I am suspicious of some form of cavitation but have few ideas on how best to test or what other possibilities may be.

All input welcome!

Firefly
C&C 29 Mk1
Rebuilt A4 (2020)
2 blade folding prop
Kept on fresh water lake so no barnacles but some winter fuzz....

Thanks in advance for the input!

Respectfully, Karl

[Dave Neptune]

Sounds like your trans needs to be adjusted, probably one notch. Can you feel the shifter "locking ~ clocking" into the detent? It is an easy adjustment depending on access to the trans cover.

Dave Neptune