1/2" drills typically turn pretty slow, take the RPM of your drill and divide it in half. Probably lower than the engine will ever idle.
Keep in mind that the cam turns half the speed of the crank. A 1/2 drill speed would be around 600 rpm meaning the crank would be turning 300 to achieve that. Not anywhere close to idle speed. I think the pressure you're getting is fine. I only get 25 psi when I prime mine
