What to listen or look for valve seat problems

[formariz 12,045]

My 520 is working fine but I am curious as to what signs it would show as far as loose valve seats go. 

Its a new engine to me so I just want to be aware  and be able to identify any issues that are typical to it.

[lynnmor 7,824]

The problem is that they can run very well with a loose seat...... till they don’t.  

 

Do the maintenance like carbon removal from heads and inspect seats then.  Adjust valves and clean fins. Keep the oil filter grommet in place.  Do a compression test from time to time, but it may not prove a loose seat.

Edited August 13, 2019 by lynnmor