Engine reduced power and clunking

[Mickey Mcguire]

I have a 2004 240 sun deck with a 350 bravo. 2 years ago replaced short block due to crack . This season motor has clunking noise at or above 2500 rpms and reduced power. Rpms top out at about 3800, we’ll below normal. Also hesitation or skip noticed throttling up from 1500 rpms to 2000. Tested on trailer with with no issues at full throttle, no clunking and limited hesitation or skip. Any ideas?

 

[scoflaw]

See if you can post a video of the clunking.. Trailer test means nothing. Clunk under load doesn't sound like good news.