Originally Posted by
canardlover
Thanks again brutus.! If you look at the second green arrow to the lower right you will notice that the C-clip is missing from the throttle axle. This is intentional since the throttle axle will not move freely and will not close butterfly completely with this clip in place. The reason is that the return spring pulls the axle axially, forcing the C-clip to rub hard against the throttle body...
.!
My intention is to have the butterfly pulled by the servo from fully closed to "full bore" and NOT utilise the idle speed adjustment screw on the carb. This enables me to shut down the engine with the throttle if need be. Does that make sense to you..?
The spring is a rudimentary thing because these carbs are mainly intended for gas powered tools and such, and you need a returnspring and idle screw for those applications.
For RC use, you can omit the spring, and IF that allows reinstalling the circlip, I would do so: Any additional clearance and vibration will cause wear at the bore eventually. Better to minimize that.
As for shutting down the engine by means of the throttle, I would not rely on that. Butterfly carbs, unlike barrel-valve carbs, do not necessarily seal off the intake (they can, they should but it is not inherently guaranteed by the butterfly design) so chances are over time, this method of stopping becomes less and less reliable.
Originally Posted by
canardlover
"Save the glow engine - they make such marvellous gassers" ..!!! I like that brutus, myself having close to 100 glow engines amassed over many decades - just waiting to be converted to gas..
I used to fly two Zehoah powered helicopters. Still have them, but decommissioned.
I exclusively fly "ex-glow" and haven't burned a drop of glowfuel in years, with the exception of benchtesting engines for friends, or helping them on the field.
My favourite and most often flown is the 5 cc ASP fourstroke, closely followed by the ASP FT160.
But all approx 10 active engines run on gas.
Not as active in the air lately...
But still running gas:
The possibilities are endless...