Strange case of evil

Hello all,



I have Bolen 158cc with B&S 10T800 series push lawn mower. Well I used it 6 year before I have noticed that it drop in power and start chocking.

I was sure all is OK (oil, gas,filter) so only things would be bad will be valve problem.



I was right, I have adjusted valves as per specification, put all back together and my engine want to fly. Started like a charm, no problem. Run for about 2-3 minutes during which I have check if all was OK.



Then I decided to change oil. I checked oil amount specification, I got 10w-40 oil and poor into engine. Prior that I have empty out old oil.



All, good. Decided to run baby again.... and I couldn`t turn it. I feel so strong resistance. I couldn`t start engine. Engine has high compression point where wont turn over.



I ask my self... what a heck. Let me check valves setting..., no all OK, springs OK. All is OK. Still can turn baby. Looks like oil pressure is building up and not allowing to engine in order to start.



I should mention that during intake valve removal on the valve I saw small o-ring with spring in side. i have check this part and is called Retainer-Valve. I assume that it was located on the same place as shown on the engine diagram.



So... engine started after adjustments. Engine is not working after oil change? I can turn engine with both hands but not with starter line?



Any idea what is wrong?



Thank you