Constant speed prop or the prop governor

What do you think I should look at 1st ?
Constant speed prop or the prop governor ?
RV-6A with 0-360, Hartzell prop and McCauley governor, both are at 1560 hrs. total time.

Changed the oil, lubed the prop and went flying. Just another day !
Set the climb power to 2400 rpm and 24"mp just like always. But when I got up to 6500 ft and leveled off at cruise there was no prop control at all. As airspeed increased so did the RPM up to about 2550-2600.

Descended to land and had control of the rpm while entering the pattern and landing. Got fuel and took off returning to base about 8 miles south with no problem setting cruise at 1500 ft and 23 squared.


Thanks,

It sounds like the coarse pitch stop was somehow changed?
Make a ?paddle? from some scrap wood, and measure blade motion from full fine to full coarse, compare to specs.

Bobs remarks sound plausible. Hope you can find the specs to compare the settings to though.

Prop blades can bind. Just try working with an electrically adjustable prop. They are awful this way. When was the last time your prop was serviced? Does the prop adjust properly with full power on the ground?

Good luck!

You don't need to use a paddle to change the prop pitch. Disconnect the governor oil line at the nose case, make an adapter, and connect shop air to it through a regulator. As you open the regulator valve the blades will move. I think mine took 40 psi to go full pitch. This is also the only way to see if the blades are binding in the hub. The movement should be smooth.

The prop works fine on the ground during run up and in the air at low altitudes.

I only see the issue up higher at cruise airspeeds. No problems with oil pressure and after checking the engine I see no loss of oil.

I always thought the TBO on the prop and governor was 2000 hrs - Totally forgot the (Or 6 years)
Today's plan is to pull the governor and prop and have both of them overhauled.

Thanks,