The last two flights I’ve noticed at cruise an occasional RPM surge of about 50 RPM by my right engine. There is an audible change and yaw so I know it isn’t an indication issue. The surge will last a second or less and happen every 5-10 minutes.
Only a couple of flights ago my prop governors were overhauled, so that seems a likely place to look. During the run up after the prop governors were put back in the gear on the tach generator in the right engine separated and lost some metal. My mechanic cut open the oil filter and found a couple pieces of metal on the magnet. The gears were replaced.
Any ideas what could be going on or what the next steps should be?
You can pull the governor and see if the governor oil screen has any metal; if so you have major (pun intended) problems. These governors are very old as some date to WWII and reconfigured to our engine/prop combination. I would think they messed up something in their “rebuild”. And because you have syncho, the problem may be the other side with the master trying to correct the issue.