Posted: 8/24/2010 20:28:16
I'm looking at a Pitts S-1C with a pressure carb and it has a wobble pump. What is the wobble pump for and when is it used?
Posted: 8/26/2010 20:17:24
On the PBY Catalina the wobble pump was used to bring fuel up to the carburetor untill the engine driven fuel pumps could take over.
We didn't have electric fuel pumps and if I remember correctly, the pump was double acting. (Pressure on both push and pull stroke)
Posted: 8/26/2010 21:59:39
I used to own the same setup that you are looking at... waaaay back in 1973.
The wobble pump in this application is to take the place of the electric boost pump. (no electrical system I presume) As I recall, you give a couple of strokes with the pump to prime the engine before start, and if you loose the engine driven pump in flight, the wobble pump is what'll get you home.
As for the PS5C carburetor, I seem to remember having to keep the mixture full rich (or the throttle full forward, I can't remember which) when the aircraft is not being flown to keep the diaphragms in the carb moist so they don't dry out. If that happens you are looking at an ovehaul on the carb.
Posted: 8/27/2010 07:29:02
I have a friend with the same set up but the pump is not putting out pressure. We tried adjusting per the manual but no luck. Does any one have repair parts or overhaul these Christen pumps as they are long out of production?