Generac GP5500 Compression

[oldnslo]

Working on a 2011 GP5500 that is slow to start and in performing compression test I get 50 - 55 PSI max. Put a couple squirts of oil in cylinder and compression did not improve. Checked valve clearances and intake is .010 exhaust is .015 so I believe that should be adequate but don't know exactly what they should be. Now I am questioning if compression release is causing the low readings. Once it starts it seems to run fine.

Any other thoughts on what can check without dismantling the engine?

TIA