Confusion reigns, Dan... Lets assume a 2700 rpm continuous engine...
Extra fuel for cooling the exhaust valves comes when the throttle is
firewalled.... Pull it back a quarter inch and you lose the cooling...
Prop speed control comes from the setting of the prop governor
adjustment screw and/or the prop lever position... This also controls
the engines power...

So, if a 2700 rpm engine is adjusted to run 2700 at full throttle and
full prop lever then you climb at full throttle and full prop lever,
gaining the benefits of fuel cooling at max continuous power...
If the engine governer is set at 2750 and the pilot pulls the throttle
back to reduce power to max continuous, then he loses the benefits of
extra fuel flow for valve cooling... He would do less damage by letting
the engine overspeed 50 rpm at full throttle and get the extra fuel...
What he should do to control the max continuous power is leave the
throttle full forward and pull the prop rpm back to 2700 - which is
where it would have been if the governor screw was set up properly in
the first place...
For bush pilots, setting the 2700 prop adjustment to 2800 is the thing
to do for short field takeoffs... They, being smarter than the average
urban pilot, know that after takeoff they reduce the propellor RPM to
the 2700 continuous setting and LEAVE the throttle full forward to gain
the extra cooling the engineers intended...

Recently I flew a C-180 for a biennial... The owner is an API and
CFI... As is usual he had extra rpm adjusted into his airplane and was
alwyas proud of how short it will takeoff... After takeoff I would
reduce the prop to max continuous RPM... Each time he would grimace and
glare at me and reach over and pull the throttle back a half inch...
"Never reduce the prop without reducing the throttle or you will ruin
the engine.", he would thunder... I would just shrug and do it the same
way on the next takeoff... He gave me heck but signed off the
biennial... He just had to change two jugs on a mid time engine...
Coincidence? I don't think so...

denny...