Cessna 152
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 195.5; Flight Crew Total 968.6; Flight Crew Type 504.8
Aircraft Equipment Problem Critical
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; General Declared Emergency
Aircraft
I was conducting flight training in C-152 with a primary student; working specifically in the pattern.Runway 24 was in use. Conditions were VMC; with a steady wind out of the west.After my student and I completed a touch and go in the left traffic pattern; Tower requested that we offset our climb by 20 degrees to the left to accommodate a much faster C130 also working in the pattern.I heard the engine pitch decrease and advised my student to reapply full power. I then checked the throttle setting and found it to be at the maximum setting. The tachometer indicated only 1900 RPM. I applied carb heat with no alteration of RPM or engine pitch. The engine was sputtering as if wanting to shut down. We were barely climbing. I took over the aircraft and turned downwind; remaining close to the airport; in case the engine failed. The engine continued to sputter. Not certain if the engine would continue operating; I advised Tower Control that I was experiencing engine difficulties. When asked of my intentions; I decided that closed runway XX offered the best chance to land safely; towards midfield. Tower redirected traffic so that I could make a safe approach and landing.The engine never shut off; and I was able to taxi the aircraft to the ramp without further incident.
An instructor pilot took the controls of their C-152 from his student went the engine began to run rough and at reduced power during a climbout from a touch and go.  They advised the Tower of the power loss and landed safely on a closed runway.