At full power/collective the rotor RPM of my Ergo sounds like it is reducing slightly.

How do I tell if it is my engine that needs tweaking, or if the blades are set up with too much top end pitch?

What size is your Ergo and what is in it for a motor?

Model is an Ergo 30 with OS32 power.

Make sure you don't have anymore then a +9 degrees pitch, if that is to much ( it shouldn't be) then drop it back to +8, don't go any lower the that. If that doesn't work then try to lean it out a couple of clicks on the needle. The OS32 should be able to pull a +9. All you can do is play with it and see what happens. It could be in your pitch/throttle courves, you mite have to play with them to. It's hard to tell without seeing it. You mite won't to find someone that knows about heli's to have a look at it for you.

Thanks for that. I think I'm running about +10 pitch and it only bogs down a little. I'll drop the pitch down and I think that will do the trick!

Get a MA optical tach. It is the best tool ever. Then you will see what the correct top end pitch should be without guessing.

I think he means MA pitch gauge?