Russ P Posted August 13, 2011 Share Posted August 13, 2011 I've recently converted an Enya 19 control line engine to rc, using a new carb from just engines. It runs fine at full throttle but cuts out when I throttle back. What is the procedure for making adjustments to get a reliable engine run from tick over to full throttle. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted August 13, 2011 Share Posted August 13, 2011 Sounds like the low end needle needs a looking at Russ. To advise you we'd need to know what type it is - air bleed or fuel flow. BEB Quote Link to comment Share on other sites More sharing options...
Russ P Posted August 13, 2011 Author Share Posted August 13, 2011 I don't know. How can I tell. Thanks Quote Link to comment Share on other sites More sharing options...
Lazygit Posted August 13, 2011 Share Posted August 13, 2011 The fuel flow type has a screw recessed in the opposite end to the high end adjusting needle. The air bleed usually has a screw in the body of the carb and is not near the throttle spindle. The jist of the adjusting is to get it running at full throttle then as yours cuts it could be rich or lean, but I suspect lean. If you have a fuel flow adjustment unscrew a little and note how much, and any running difference. You may need to open it more and try again. If it's an air bleed, you screw it in to richen (it reduces the air). Try this then if you get it running at low throttle, readjust the high running screw. They are interdependent, so you have to tweak both to get it right. Once they are about right, let the engine idle for at least 30 seconds, then open the throttle. The engine should pick up smoothly. There is a useful test to check correct low setting. Get it idling then pinch off the fuel line. The revs should rise after a short delay then the engine will stop if you keep it pinched. If it dies straight away it is too lean. Which model carb is it? Edited By Lazygit on 13/08/2011 21:28:35 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted August 13, 2011 Share Posted August 13, 2011 A way to get the low end needle about right: connect a new bit of fuel tube to the fuel inlet. close the throttle trapping a pin in the barrel hole so it cannot be closed completely - just nearly. Blow through the fuel tube. Turn the low end needle - either closing on opening - until the you cannot blow through the tube. Now reverse the direction you turned the low end needle until you can just hear the start of the hiss of the air passing through the carb. Its important that you get it just on the point where the hiss starts. This will be a good first guess at the low end needle position. TBH I find that it often gets it pretty well spot on first time! BEB Quote Link to comment Share on other sites More sharing options...
Russ P Posted August 13, 2011 Author Share Posted August 13, 2011 Series 3 Twin Needle Carburettor for 10-21 size engines It's a Just Engines series 3 twin needle carburettor. I'll give your suggestions a go. Thanks for your help. Russ Quote Link to comment Share on other sites More sharing options...
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