PDA

View Full Version : new OS91 SZ PS acting crazy on Synergy

R-4-L
02-15-2007, 09:56 AM
well we've been trying to test out a synergy with everything new in it including the engine and SB18 muffler.

tuned as per manual and slightly rich as with all engines.

as soon as we start the engine, it runs good for a few seconds and all in a sudden it SCREAMS as if it was given full throttle for 3-5 seconds, then smooths out, then repeats the same thing over and over,,

throttle servo is stationary at idle when this happens, nothing suspicious there. checked for bubbles in the fuel line there was nothing and no leakage.

I don't know if I should suspect the pump (regulator) of the carb or what..

Any ideas?

Thanks.

Ali
z11355
02-15-2007, 10:12 AM
mmm, it would be helpful if you explained how you plumbed the engine.
R-4-L
02-15-2007, 11:12 AM
ok, muffler goes to tank, tank goes to backplate IN, backplate OUT goes to carb's regulator.

I am going to take a closer look at the engine, if only taking out the engine from the heli was like raptors :?
DavidH
02-15-2007, 11:20 AM
The vent ( pressure) line should just be hanging open to the atmosphere. Most of the pilots I have seen use the SZ pumped engine do not use muffler pressure. They just vent the tank to the atmosphere.

David
R-4-L
02-15-2007, 12:27 PM
in the manual they mentioned that I have a choice between muffler pressure or not.. david you think this caused my problem?
pilotError
02-16-2007, 09:29 PM
Could your clutch be slipping?
Peter
03-17-2007, 06:19 AM
put the motor in a decent heli ??? :D :D :D :D :D :D
Jerry
04-14-2007, 11:18 AM
I've run mine on exhaust pressure and open vented - your situation will not be caused by using one versus the other.

Jerry
wjvail
04-18-2007, 09:08 AM
In order for and engine to run at high speed it needs air (no kidding right?). Given that the carb is in fact at the idle position (it is right?) the air must be coming from somewhere.

Is the carb properly seated?
Is the carb pinch bolt sealing?
Are all the back plate screws installed and tight?
Is the tube from the backplate pressure tap properly connected to the pump?
Are all the needles installed and sealing?
... and the list goes on.

If the carb is closed and the engine is "screaming" air is coming from somewhere.

Bill