Bonanza 36
Flight Crew Commercial; Flight Crew Multiengine
Flight Crew Last 90 Days 5; Flight Crew Total 2400; Flight Crew Type 50
Aircraft Equipment Problem Critical
Flight Crew Overcame Equipment Problem
Aircraft
En route for air show; decided to turn back because weather at [destination] had gone to IFR.  We were at 2;500 feet with flight following.  Upon 180 degree turn back to [the departure airport]; had engine roughness.  Tried to lean and other methods; could not stop roughness. Flew to ZZZ.   Was passed off to ZZZ tower. Verified they knew of [our] status. They knew.Was cleared by tower to land on 13. I flew high and descended rapidly to land so that if I lost power; I could still make runway.  I decided to lower gear on short final after side slip to kill speed. When speed was at gear extension speed; lowered gear and no green lights came on even though gear sounded and plane acted like gear went down. We did a go around and flew around the airport about 4 times to trouble shoot gear lights.This was a difficult situation having a possibility of an engine failure with no green lights for gear. The red 'in transition' light did work for gear and circuit breaker was not popped.During flight around airport; tower made a turn request that I refused to accept and told them I needed to go opposite direction and was using emergency exception. Tower had no conflict that we knew of.  Had tower verify gear looked down and locked.Eventually landed with no problem. Got off runway and shut down. Had tug take plane to hangar.  Found a bolt and a screw under the nose gear on the ground. They could have just been there by coincidence. Unable to look under plane to see if any problems as we didn't want to have it collapse on us.Mechanic inspecting plane today.One cylinder was replaced just a few days ago by mechanic.JPI engine analyzer did not show anything abnormal in flight.Note: On short final; controller told us that our gear was not down. We knew but; really appreciated controller looking out for us. When you have an emergency; it is easy to forget something. She had no way of knowing my plans. I really hated having to go around.All well. No accident; no injury.
A BE36 pilot reported experiencing engine roughness and a problem with his landing gear.