Optech Key Veteran Location: Vista/Oceanside, CA.
| Enya .50 Idle problemsThe problem with the Enya .50 carb is the design of the idle circuit. Its a two needle system that is an old design. I don't know why Enya still insists on designing their carbs this way. I've got the airplane version of this engine and have tried everything I know to get it to idle. I've bought new parts to no avail. In fact, two of the low speed needle I've received had different tapers to them. Neither has worked. As far as I'm concerned the engine is a control-line engine til a proper carb can be found for it. It runs great at full speed but the carb just sucks.
The first problem is the way the low speed needle meters the fuel coming out of the main jet. The low speed needle is a tapered design that meters fuel by sliding into the main jet. If for some reason the needle is jammed into the main jet hole, the hole is widened and the adjustment will never be correct. You can inadvertantly widen the hole while playing with the carb after you unpack the engine if you don't first back out the needle. Also, you must very gently screw in the needle when you want to find the bottom. If you screw it in and bottom out too hard, or force it to be tight, you can widen the hole or even crack the main jet opening.
The other problem is that in order to get the idle adjustment set, the engine barrel must be opened to the position you want it to idle at which point the needle is turned in till it stops, then backed out the appropriate number of turns. OK... all fine and dandy but what happens when you now close the throttle all the way to kill the engine???? You got it, the low speed needle gets jammed into the main jet hole. If you try to set the idle needle with the throttle all the way closed, at the idle position the setting is way too rich. Its a total no win situation on a heli. The OS low speed needle meters fuel by sliding over the main jet hole which is a "Cat Eye" type of hole. This is a much better way to do it as the adjustment can be set no matter where the throttle barrel is in the low speed portion of its travel.
Through all the parts, all the runs, all the adjustments, I never did get a satisfactory idle. At best it would idle for a few seconds but the transition to full speed without coughing or quiting could never be achieved. It seems I could never get the carb lean enough.
I know one fix for the older OS .46 engine was to file a slot in the carb barrel or drill a hole in the carb body to lean things out for idle and transition. This MAY be a fix for this engine as well.
Let me know what you find,
Mike |