Waving when in loiter

[gediminasgu (GG)]

Hello,

After changing motor for my plane (same model, just different motor), when the plane is in loiter it started to wave. It accelerates, pitching up, then deaccelerates and pitching down.

Any ideas how to fix it or what to look for?

Thanks,
Gediminas

[Gregmaan]

Try it in manual mode. Maybe you should only check your COG…