[JimMac53]

If changing tubes doesn't help, you might want to check C4. I have recently completed the restoration of a Murphy A242 and A252. The A242 suffered from exactly the same problem as yours, where the A252's FM gain was hot -- too hot. After about a week of listening to the A252 in my office, it stopped working with nothing but howls on the FM band. The solution for both the A242 (poor FM gain) and the A252 (to much gain and eventually oscillation) turned out to be the same component (even though their designs are different, they are similar). I just had a look at the schematic of the Bush VHF61 and it's similar to the Murphy's. I would have a look at C4 (540 pF?, I can't quite read the value on the schematic I'm looking). In the Murphy's, this capacitor is critical to the gain of VHF; too low and it breaks into oscillation; too high and gain is killed. In the Murphy's this capacitor was a Hunts. After I pulled out the capacitors, I measured them and sure enough in the A252 the capacitance had dropped by about 150 pF where in the A242 it had gone up.