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pauldan181

Well Known Member
What is the typical failure mode of an engine driven fuel pump? I have an carbed 0-360A1A. The engine started normally but the fuel pressure slowly dropped to zero. I turned on the electric pump and the pressure comes up to 4 psi. I repeated this several times and finally with the boost pump off the pressure slowly came up to it's normal 5 psi. This is the first time the fuel pressure failed to come up right after starting.

I put the plane back in the hangar, took off the cowl and inspected the fuel system and all seems normal. The pump overboard drain line was dry as well. Is this the first signs of a dying pump?
 
Service Bulletin

Check Lycomming Mandatory Service Bulletin # 548A.
It came out August 31,2005.
Mine was one them.
 
rich said:
Check Lycomming Mandatory Service Bulletin # 548A.
Click to expand...

Thanks for the heads up on the SB Rich. I checked and my S/N is not affected. The engine was purchased new from Aerosport in 2005, first run in 2007 and has about 350 hours.
 
Same type problem but fixed with a new engine!

Paul, I have to say my engine (O360-A4M) did a very similar type of fuel pressure anomaly but only if the plane had not flown for about a month. I just overhauled the engine recently and changed the pump but the symptoms
on the old pump were almost identical to yours. It seemed to "drain" back to the tank after an extended time, never a problem if flown weekly or daily. Mine did seem to keep fuel pressure(after engine start) if the aux pump was on for 30 seconds or so. Then, never a problem with the engine driven pump,4psi.

BTW, went out to the garage and pulled the old pump, yep, it's on the service bulletin list!! Man, did I miss this one!!!

Engine ran fine for......2460 hours.....with no pucker factor. :eek:
 
Check the finger screen where the fuel line goes into your fuel servo. Often ignored, these can plug up.
 
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