Cheetah; Tiger; Traveler AA5 Series
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 12000; Flight Crew Type 250
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
After completing maintenance [at a nearby airport]; we departed IFR for the return to home base. An oil change; brake check; and the replacement of an aircraft [exhaust] stack had been performed. The aircraft departed with full tanks on the right side tank. After approximately 90 minutes of operation -departure and cruise at 4000'- the left tank was selected to balance the fuel and the next hour of flight was flown on that side of the fuel system. (Note: the Grumman AA5A does not cross-feed. The aircraft carries 51 gallons of usable fuel.) Selecting the right side tank again; and approximately 30 minutes from the destination; we were vectored toward [destination]. Shortly after the vectors began; low fuel pressure was noted; followed shortly thereafter by diminishing power; followed by surges. Suspecting a fault related to the recent maintenance; we immediately turned toward the nearest airport in the interest of safety. Nearing [divert airport]; we performed an emergency check on the system; part of which involved selecting the left (fuller) tank. Power was immediately restored. Additional checks were completed and the emergency was cancelled with a return to 4000' assigned altitude. The flight was completed safely.On arrival we investigated the right-hand tank fuel vent and found it clear and also a small amount of fuel still remaining in the right tank as well. The left tank still contained 15 gallons of fuel.
Grumman-AA5 pilot reported engine roughness in cruise flight that may have been related to fuel system management.