fuel dripping from carb on 120fz
09-30-2013, 05:52 PM
#1
fuel dripping from carb on 120fz
I have a ys 120fz that i have had for years with no issues till a couple months ago it broke a rod in flight and i damaged the plane but anyways i ordered new parts, piston, ring, rod, valves i put it on my new plane and have the regulator flush. when running there is alot of air bubbles in the line from regulator to carb, i replaced the line with no effect. also fuel drips out the carb while running and after i shut it off. I have taken the regulator apart a couple of times, replaced the plunger but central is out of stock on the diaphram. my old diaphram looks ok so not sure what the problem is. if i screw the regulator in it goes lean and wont run. any help appriciated. here is a video that shows air bubbles and fuel dripping.
http://youtu.be/YJcFXfvb1HM
10-03-2013, 07:56 PM
#4
It looks huge rich to me.
Try replacing the plug with a new OS-F.
I had something similar last week when the 140 Sport was acting very rich, fuel dripping, would not run without the glow driver attached.....but the mixture was not rich.
I replaced the plug and it ran perfect.
Try replacing the plug with a new OS-F.
I had something similar last week when the 140 Sport was acting very rich, fuel dripping, would not run without the glow driver attached.....but the mixture was not rich.
I replaced the plug and it ran perfect.
10-03-2013, 07:57 PM
#5
10-04-2013, 04:16 AM
#6
Yea thanks. It is running better. My only concern is the hs needle is only 1 turn out and the regulator is about 2 turns in from flush. It is running good just thinking maybe regulator letting too much fuel in. I still get lots of air bubbles in the line after regulator is that normal?
10-04-2013, 06:13 AM
#7
Yea thanks. It is running better. My only concern is the hs needle is only 1 turn out and the regulator is about 2 turns in from flush. It is running good just thinking maybe regulator letting too much fuel in. I still get lots of air bubbles in the line after regulator is that normal?
Usually the regulator will be too rich and the n/v is too lean which is then adjusted for best high speed....but then the idle and transition will be too rich.
In addition, the excess air bubbles in the fuel line may contribute to the lean condition.
Typically, the regulator screw should be a half a turn in from flush....in is lean, out is rich.
I think I would take apart the regulator and ensure that the spring is positioned properly over the rubber plunger valve. The large end of the spring should be under the brass screw.
This spring can be off to one side and jamming the plunger which will make the mixture weird. The air in the fuel line would be an indication of this....or perhaps trash in the plunger seal area.
Check the cam timing too....at TDC the dot on the cam should be vertical.
