This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
The mission was to reposition a Cherokee 6 from ZZZZ to ZZZ1 where the owner would meet me. I had previously flown this aircraft a few years prior, and it was one of the nicer planes in ZZZZ.
During pre-flight, I noticed that there was a lot of dirt in the fuel. We spent a good amount of time draining the tanks, both with the fuel drains on the tanks and out of the gascolator to remove any debris.
After that, I had an uneventful flight across the Gulf of Mexico, stopping in ZZZZ1 and eventually ZZZ3. After clearing customs in ZZZ3, I taxied out for departure.
After getting clearance for takeoff, I applied power to taxi onto the runway and the engine suddenly stopped. I restarted the engine and taxied to the ramp, thinking that I had put the fuel selector accidentally out of its detent and that caused it to quit.
However, upon taxiing to the ramp, the engine quit again. I saw the fuel pressure was quite low, and decided to spend the night in ZZZ3 and have the mechanic look at it the next morning.
I met with the mechanic and we worked on the plane. He removed the gascolator and cleaned it, finding that it had water and other contaminants. We did the same with the wings and ensured there were no contaminants in the fuel.
After discussion with the mechanic, he thought cleaning the gascolator should fix the problem, but that at the higher temperatures the plane could be experiencing vapor lock at lower RPM settings and that I should run the boost pump at low power settings and idle. He put a logbook entry in the airplane’s logbook for the work performed.
Upon taxi out and run up all engine indications (fuel pressure, etc) were within limits. I took off and stayed within gliding distance of land. After about an hour in flight and when I was about 30 miles east of ZZZ4, I noticed the fuel pressure gauge was showing fluctuations and it moved from 30 to 25 and continued down. I knew at this point the engine driven fuel pump was failing and decided to divert.
Suddenly, the engine quit and I completed a restart using the electric backup pump. I received priority and headed to ZZZ5.
At first the electric pump couldn’t keep up with the fuel demand and was causing engine power surges (extremely lean mixture) and it was fluctuating. I reduced power significantly to maintain a lower speed and altitude but the electric pump continued to fluctuate.
After the power reduction I had good fuel pressure and decided to divert to the nearest suitable airport that had maintenance available. I didn’t believe this was a land immediately situation due to the fact that the backup fuel pump was operating and engine indications were normal and I had no reason to believe that would deteriorate. I landed uneventfully and taxied to parking, with the engine barely running.
In hindsight I shouldn’t have let the plane owner and mechanic pressure me into going when we suspected that the engine driven pump was “weak.” Ironically, the owner has the fuel pump sitting in his house so he knew it was having problems and failed to tell me before I flew five hours over water outside of gliding distance of land.
I should never take failing to perform to minimum mechanical or operating standard as an “airplane nuisance” as the mechanic and owner stated. If the POH doesn’t call for running the boost pump on the ground and it requires running the boost pump to run, that is an airworthiness issue and should be addressed prior to flight.
Overall everything went well and the backup performed its purpose.
Primary Problem: Aircraft