Looking for ideas on Clogged injector Cause

lr172 · #1 03-24-2019, 02:50 PM

On my flight home from Missouri yesterday, I noticed #3 CHT at 275, while all others were 340 in cruise. I confirmed during flight that ignition was behaving properly and my first guess was debris in the injector. Pulled the cowl today and that turned out to be the issue. Now resolved.

My question for those with more experience, how often is this an indicator of a developing issue in the FI system vs a simple anomaly in the S*** happens category. FI system was installed 500 hours ago, so not a typical piece of debris introduced by the installation process. Though I suspect is could be that with the debris clinging to something else for a LONG time. I can't imagine this piece got by two different filters.

Larry

flyinga · #2 03-24-2019, 03:07 PM

I went to a FI seminar at OSH a few years ago and was told that the most common cause of clogged injectors was lint from mechanics rags. Apparently wiping/drying injectors with a shop rag after cleaning can leave lint.

Steve Barnes · #3 03-26-2019, 10:03 PM

I had a problem with clogged injectors and found it was pieces of rust from inside the servo. The orgin of the rust was from a steel bolt/plug that was hollowed out and the rust formed inside. It was replaced with a stainless one.

Steve

pilotkms · #4 03-27-2019, 04:22 PM

Injectors or Nozzles ?? I was advised that my Silver Hawk FI system has nozzles and they need to be cleaned at annual Condition Inspection. Just did my CI and pulled the nozzles. Each had a coating of black grime. Used a Sonic cleaner ($20 from A) with some special sauce and they were renewed. No rags used. Ready for another year.

BillL · #5 03-27-2019, 04:30 PM

Many things can deteriorate and generate debris. I helped a RV owner OSH last year that ended up being a clogged nozzle. It appeared to be a tiny speck broken off of some thread sealer for one of the 1/8" NPT holes in the spider. The speck was barely larger than the nozzle entrance. It was likely aging for quite some time before it caused his trouble. An expanded photo of the interior revealed a tiny bead of sealant around each fuel tube adapter.

There are "final filters" in systems for a reason.

lr172 · #6 03-28-2019, 09:22 AM

Thanks for all of the input.

Larry