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Fuel Servo issues RSA-5AD1

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Registered Users
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Aug 2, 2014
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I am having an issue with starting my Pitts that has a Superior IO360A1A engine. It has a cold air intake, inverted systems, Christian Wobble pump, and the Title listed servo unit.
When cold, it has always started after a couple of blades (3 blade prop).

I am unable to get it to fire now. Spark has been verified. Lots of starter cranking has resulted in fuel out the exhaust. (4 in to 1)
Cleaned and replaced injectors with no effect. Confirmed fuel in all 4 lines from wobble pump.
Fuel was also observed coming out of the servo unit after unsuccessful attempts.
The engine appears flooded. It did try to fire with mixture lean / no wobble action, but no continuation when trying to advance mixture control.

It seems to me that the fuel servo is the obvious place to look. I looked at a troubleshooting guide on Precision Airmotive's website, but most of their tests require the engine to run.

In looking up the parts list number on the servo unit on the Precision Airmotive website, 2524673-8, it lists 2 applications; both of them are 540's??

I believe that a previous owner got this unit from Airflow Performance in 2005. The logbook entry says it was sent to "Precision Airflow Performance".
I am guessing that the advice here will be to contact them about an overhaul / replacement.
I just wanted to check with the braintrust here to see if there were any suggestions on things to try or options.

Thank You,


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