kbkindle     i have a 2004  hpdi  200hp small block   last year  it would turn  5300 rpm's   at 63 mph    this year it turn's 5000   at 58 mph   nothing has changed as far as boat   weight   etc  it runs soooooooo good i hate to do something with it  , but there must be a reason and maybe it will be bad farther down the line  what say you yamaha  experts  kb

  THER ALSO SHOULD BE A MOTOR TOPIC ON THIS SITE  KB

you sure you havent done any thing diffrent like change the lower unit oil, change the oil brand, new prop, are you triming the motor up more less ????

My first question would be, are we talking the same time of the year.  If you were running those speeds and rpms back when the water and temps were cold, and are using warm water and temps as a reference now, you can't do that.   The motor looses about 300 rpm during the hot summer water and temps from what it will run in cold water and air temps.

kbkindle here      yes ia'm sure i have not changed anything on motor or boat and when temp this summer was 90% and know 55 % the same thing i guess ill take it into dealer and see what he can find. i dont care about the difference in rpm's and mph just wondering it will harm motor running this way rather than what yamaha says like run at 5500 rpms it runs so darn good got me confused maybe just run it and say the he$$ with it? kb