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| ...and another good argument for having a bleed-bypass circuit. ;-)
Mark On Sun, Jul 3, 2011 at 9:13 PM, Steven W. Boese <SBoese@uwyo.edu> wrote:
My standard shutdown procedure has always been to cut the power to the fuel pumps until the engine stops and then shut down the power to the rest of the system. In early May, after sitting overnight at an airport away from home, the engine started on only
one rotor and then started to run on both rotors after a few seconds. It did this twice more after being shut down at least overnight. Finally, the engine refused to start at all. Removing the spark plugs indicated a flooded condition, much more evident
on rotor one than rotor two. Removing the injectors and pressurizing them on my injector test rail, the primary injector of rotor one leaked fuel at a slow drip and the secondary injector of rotor two would form a drop of fuel that would evaporate fast enough
that it didn't actually drip. The other two injectors remained dry. Since all those injectors were most likely the original ones from 1986 and had well over 100,000 miles before use in the aircraft, I replaced them with new ones from RC Engineering. I haven't
had flooding problems since the replacement. Apparently, there was enough fuel that could leak through the injectors and cause flooding even after the shutdown procedure that involved killing the engine by shutting off the fuel pumps. Probably, heat soaking
the firewall forward fuel lines and fuel after shutdown resulted in pressure buildup and enough fuel leaking through the worn injectors to cause a problem. Just my recent experience for what it is worth.
Steve Boese
RV6A, 1986 13B NA, RD1A, EC2
I think that the idea is to shut down the pump(s) with the engine running. The injectors will continue to do their thing, & the engine quits when pressure drops too low to flow through the open injectors.
Charlie
On 07/03/2011 02:28 PM, Kelly Troyer wrote:
No !!...........The check valve is located in the inlet to the pump and will hold regulated pressure
indefinately or until relieved by leaky injectors or the afore mentioned bypass sysrem.........
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo
From: Ernest Christley
<echristley@att.net>
To: Rotary motors in aircraft
<flyrotary@lancaironline.net>
Sent: Sunday, July 3, 2011 2:15 PM
Subject: [FlyRotary] Re: Leaking injectors?
On 07/02/2011 09:52 AM, Kelly Troyer wrote:
Ernest,
Your EFI fuel pumps have a check valve in them and will hold regulated pressure
for a long time or until leaky injectors relieve this pressure..........Short of
replacing
the injectors the fix is to put a pressure relief
orifice from the fuel pressure line to
the fuel return line...
Shouldn't shutting down by cutting power to the fuel pump relieve the pressure, though?
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