Perry Pump Questions
05-21-2009, 03:28 AM
#26
Join Date: Feb 2007
Location: Norco, CA
Posts: 938
Likes: 0
Received 0 Likes
on
0 Posts
RE: Perry Pump Questions
ORIGINAL: gaRCfield
Not really sure what happened: pump seemed to be working well but I was really nose heavy. I moved the engine back on the mount and had to relocate the pump, and 5 subsequent flights resulted in 4 dead sticks and a ripped out undercarriage.
I tried re-routing the return line from directly into the tank stopper to a 'T' just before the pump, as in the diagram. I seemed to be having air issues, could not get the engine very rich at WOT, and again had a boggy transition.
Removed the 'T' system and tried leaning out the mixture valve. Now idle mix is very lean, high end is pretty leaned out, and although transition is good the engine loads up with excess fuel if you have the stick anywhere in the middle of the throttle range (aka flying the plane). However no dead sticks.
Not really sure what happened: pump seemed to be working well but I was really nose heavy. I moved the engine back on the mount and had to relocate the pump, and 5 subsequent flights resulted in 4 dead sticks and a ripped out undercarriage.
I tried re-routing the return line from directly into the tank stopper to a 'T' just before the pump, as in the diagram. I seemed to be having air issues, could not get the engine very rich at WOT, and again had a boggy transition.
Removed the 'T' system and tried leaning out the mixture valve. Now idle mix is very lean, high end is pretty leaned out, and although transition is good the engine loads up with excess fuel if you have the stick anywhere in the middle of the throttle range (aka flying the plane). However no dead sticks.
I don't think your problem is too much pressure. Doesn't make since if you can't richen the high speed needle. What does make since to me is that there is a partial obstruction in the carb. This would restrict high fuel flow during WOT. Since it previously worked until your mod to balance your plane, I suspect that something got inside the line during the mod and is now wedged in the carb. Also adjusting the pump to provide lesspressure seems to me would make this worse. IMHO
