When IS PUMP Needed??
 

I have a ST 2300 and it runs well on the ground but I have had 2 dead sticks in air. I was watching the fuel flow to carb and it appears to have good pressure at anything over idle but at idle it appears to not keep fuel under pressure. It does run well on ground howerve. I was considering buying Perry pump but don't know if I need it or not.

RE: When IS PUMP Needed??
 

Are you using the stock muffler ? Have you checked all the fuel lines to
make sure you are not losing pressure ?

FBD.

RE: When IS PUMP Needed??
 

I have checked all lines and have installed small zipties on fule line. I have a bisson pits muffler that I have peened the ends of the 2 exhaust tubes to increase back pressure (just slightly larger opening areas thatn original muffler). The engine runs well on the ground but in the air it has deadsticked twice. I have a large fuel line with large brass tube in stopper and large clunk. It appears to me to have good fuel delivery at 1/4 to full throttle but at idle and just over the pressure just doesn't seem to be there to push fuel to carb. I haven't tried holding the plane vertical yet but will try that as soon as I can talk my wife into controling radio.

RE: When IS PUMP Needed??
 

What you are saying sounds just like I had on a .46 engine whith a Pitts muffler. I plugged the outlets, played with needle settings, and it would run great at or above about 1/3 or above. I had almost given up until I installed an oscillating pump and all was well in the world. It sounds like the muffler is not generating enough back pressure to supply the fuel at idle. Have you tried to close one out let all of the way??? Not sure if the little pump I had would even keep up with your engine at idle.


Dru.

RE: When IS PUMP Needed??
 

I always use pumps or regulators now. The engines just run way better and actually use less fuel (more efficient fuel delivery).