hi guys,my motor checked 30 psi on both cylinders and would not stay running,so i took advice from here and put new carb kit,head gasket,all new fuel lines and filter plus sanded head on glass, plus put motor up and poured sea foam down both cylinders and let soak for over 8 hours,then checked compression again and at still says 30 psi on both cylinders,so i pull and pull some more and it finally starts,this time for about 4 or 5 minutes and then dies,by this time both my arms are worn out so i'm wondering if the rings are bad,when i took the head off some one had already decarbed it, it was clean,so i'm thinking the guy i bought it from knew it had low compression,but would it even run at this low psi,i put my thumb over both plug holes and turned it slowly and it does have suction,any thoughts,thanks...