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The VAF News - 2.9.2026. #6492.

DeltaRomeo

doug reeves: unfluencer
Staff member
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TL;DR: Found debris in the injector(s) which caused my partial power loss - switched to loctite 565 instead of Permatex on the fuel pump inlet and cleaned the whole fuel system.

A bit of system background - I have an Andair Fuel Pump and Filter, Silverhawk Fuel Servo with a Precision Airmotive Fuel Spider and Nozzles. My Specific installation has the Andair fuel filter separated from the fuel pump by a tube, as a result I have an NPT to flared fitting on the fuel pump inlet. This fitting needs to be sealed of course, and when I originally installed the fitting, I used Permatex #3 aviation form-a-gasket. I came back a few days later to find a small drip of brown Permatex and a faint smell of fuel; I had a weep.

I took the pump out of the plane, removed the fitting and cleaned the threads out, removing all the old sealant. I applied some new Loctite 565 instead (per recommendations on these forums for when Permatex doesn't work), and that solved my fuel leak. Maybe my Permatex was old, not sure why it didn't seal.

A few weeks later (early Jan 2026), I did some ground runs in preparation for the first flight. The engine ran rough, i couldnt get the mixture right, it rose >300RPM when going to idle-cutoff, EGTs were all over the place, and black smoke was observed from the exhaust. I removed the injectors and found some debris in the #4 restrictor. I cleaned it out, and the engine ran wonderfully. I did all my ground runs up to full power, and all the tests passed after that.

After my first flight engine issue I immediately suspected debris in the injectors. Partial power loss, 1, 2, 3 EGTs dropping suddenly (I suspected overly rich fuel flow cooling the EGTs and causing poor combustion), and black smoke see by my ground observer, seemed like an exact replica of my initial ground run woes. Well I did indeed find debris in the #4 restrictor. It looked like some curved, dried Permatex from the pump threads that made its way to the engine.

I have since cleaned out and flushed the whole system, re-cleaned the threads on the fuel pump (extra careful this time), and have run the system all the way to the nozzles showing even flow from all four nozzles. Engine ran great after putting everything back together, all EGTs were even, and CHTs similarly were all within normal ranges (for the 3 minutes I ran the engine).

I will hopefully not be discussing my next flight due to it being a boring, routine flight.



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