582 full throttle RPM changes? why?

[wildirishtime]

Anyone seen this? Sometimes I go to full throttle
I get 6000RPM static (tied down), trottle back to
check other things like EGTs or whtaever and
THEN I run it BACK UP and I'll get 6400 RPM. I'm
pretty confident I can feel the difference so it's not
the RPM gauge or related electronics, I'm pretty
confident it's the motor.

Why is this? No my blades are not loose. What
can I do about it? Or should I ignore it for now and
see if it improves?

~Wild

[SkyPirate]

do you have the oil tank or premixxed fuel? sometimes with pre mixxed if it's not "mixxed " you will get different RPM and may may not get hot EGT's,..
any kinks in the fuel lines? last time a decarbon was done? and possible some dirt in the carb?

[wildirishtime]

Oil tank, not pre-mixed. Anyone seen this happen
with older E10 Premium gas? my gas isn't that old so I don't think
so, and I drained the sump of course.

[GDN]

hello after carb cleaning and setting my full throttle decrease about 200 rpm never knew why ? Didn't change propeller pitch. I think it depend of air density .
My rpm never changed since that moment.

582 Grey oil tank

See you

[wildirishtime]

What I mean is my max RPM changes DURING THE SAME FLIGHT. One time on climbout it's 6500 (first few takeoffs) and then drops back to 5900RPM for the rest of the day of touch and goes.

Why?

Any ideas appreciated. Carbs are clean, rebuild kits, jetting looks good and burns right, etc.

Thanks,
-Wild

[wildirishtime]

there's no surging in the power - i assume in your problem you described you had a noted surge and likely an increase in EGT's?