Shadin Fuel Transducer issue?

[BorealOne]

Ok, so I'm 2h into a 6h leg (KIAG to KORL) today, happy to be out of the Great Lakes klag and cruising over the Shenendoah, when my heart nearly stopped as the Shadin showed fuel flow dropping precipitiously from 12.3 to 8 to 7 to 5 to 0...

I flipped on the boost pump, and quickly hit 'nearest' to see whether there was a reasonable airport within range. But luckily enough, nothing else exciting happened. CHT/EGTs remained rock solid, and the MP and RPM gauges didn't move a whisker. So i turned off the boost, and again, nothing happened...

Much relieved, I watched the Shadin randomly generate fuel flow numbers for most of the rest of the trip. It was correct about 1/2 of the time, and for the last 40 min from Jacksonville to Orlando, seemed to be working just fine. The engine remained completely oblivious to whatever the Shadin was doing, and hummed away happily without so much as skipping a beat.

So, I'm now on the ground at ORL, wondering whether a) put this down as a transducer going south and add it to the sqawk list for my next visit to my friendly neighbourhood Mooney Service Centre, or call around S. Fla to see if there is someone who wants to have a look at this before Christmas, when we continue down to the Bahamas.

Thoughts?

 

[jwilkins]

One of my previous Mooneys had an FS-450 fuel flow meter.

At one time it showed significantly reduced fuel flow, then went to '0'.

My mechanic said 'sometimes the turbine in the sending unit gets jammed with debris but it usually clears itself'. I just couldn't let it go and asked him to check it out. He took the transducer out of the fuel line and carefully back-washed it with fuel.

There was a very small flake of fuel tank sealer which was just enough to slow down and then stop the turbine in the transducer. The turbine in the FS 450 (and probably all others) is built to allow full fuel flow even if the turbine fails or gets stuck.

I suggest you get it checked  (it may be something completely different) and hope it is something as simple as what we found.

Happy Holidays!

Jim

 

[John Pleisse]

Careful...Shadin sometimes prices replacement transducers high, forcing upgrades.

[Jfinch]

I had a similar issue with my fuel flow about two weeks ago, when departing the Bahamas.  Both the Shadin and the factory fuel flow went erratic, but the engine kept running normally and all other engine parameters were normal.  The readings went from normal to as high as 45 gph, and then all the way to zero, and back.  This continued for the next two legs of my return flight.  When I took it to my mechanic, everything was normal and he couldn't find anything wrong.  It has worked well since then.

I do have ocasional fleks of something (I suspect detoriating sealant) in my fuel when I sump the tanks during preflight.  I am having both tanks fully redone at the end of January.  I'm suspecting maybe one of those fleks of sealant may be the culprit for my fuel flow issue??

 

[fantom]

Could also be dirty fuel, FBO tank or even old gas hose coming apart. Did you fuel up in the BAhamas?

[Jfinch]

Quote: fantom

Could also be dirty fuel, FBO tank or even old gas hose coming apart. Did you fuel up in the BAhamas?