Rich too Posted April 19, 2014 Share Posted April 19, 2014 I removed the spring on my Zenoah 23 and never had a reliable idle. So, I am now installing a DLE 20 and the instructions say to disconnect the spring tension, which I am reluctant to do. What do you do? I tried a Google search and opinion seems very divided. Why do they bother putting them on, if they then advise disconnecting so that there is no tension? Rich Edited By Rich2 on 19/04/2014 17:21:15 Quote Link to comment Share on other sites More sharing options...
iqon Posted April 19, 2014 Share Posted April 19, 2014 My spring is off and works, if you leave it on you are fighting the servo don't take it off completely, just unclip it.. Quote Link to comment Share on other sites More sharing options...
Rich too Posted April 19, 2014 Author Share Posted April 19, 2014 Thanks, but why is it on there? Any other opinions? Cheers Rich Quote Link to comment Share on other sites More sharing options...
iqon Posted April 19, 2014 Share Posted April 19, 2014 guessing the carbs are used on other things like lawnmowers, blowers etc.... Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 19, 2014 Share Posted April 19, 2014 Yep Walboro carbs on most petrol equipment no servo's on them Quote Link to comment Share on other sites More sharing options...
Rich too Posted April 19, 2014 Author Share Posted April 19, 2014 Mmmmm, thanks guys. I have read a few threads on other forums and opinion is very divided, however it is agreed that the load on the servo is negligible. On that basis, and the fact that idle will be more consistent, and the engine will idle in the event of linkage failure - I am going to try with the spring.... Cheers Rich Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 19, 2014 Share Posted April 19, 2014 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ultymate Posted April 19, 2014 Share Posted April 19, 2014 You can disconnect the spring but as Tom has said above do not remove it as it will cause the butterfly to vibrate laterally inside the throat of the carb and cause premature wear and poor idle due to air leaks around the butterfly at idle. The load on a servo is negligible, in fact wherever possible I leave the spring connected and just use a thin boden cable to the servo to pull the throttle open and rely totally on the spring to close the throttle, doing so limits the amount of vibration being passed directly to your throttle servo Quote Link to comment Share on other sites More sharing options...
Ronaldo Posted April 19, 2014 Share Posted April 19, 2014 Ok Rich. Agreed there's not a lot of resistance on the spring that a decent metal geared servo can't handle, but I prefer to unclip it, ... cos' ''Resistance is Futile'' ( whoops sorry, couldn't 'resist' adding a bit of Borg lingo ) If you do decide you don't want it on, just unclip it from the arm and leave the spring on the throttle arm's shaft. this will take up any play, preventing wear on the shaft caused by vibration when the engine is running, leading to sloppy throttle response and fuel leaking from the throttle arm shaft. I've always found that most throttle arms have a bit of play and can slide in and out freely when the spring is removed completely I do this with all my petrol engines and have no problems with the idle setting. Ronaldo Quote Link to comment Share on other sites More sharing options...
Ronaldo Posted April 19, 2014 Share Posted April 19, 2014 ..... and as I forgot to mention as Tom and Ultymate said above , prevents wear on the butterfly. Thanks guys, Ronaldo Quote Link to comment Share on other sites More sharing options...
woody Posted April 19, 2014 Share Posted April 19, 2014 I disconnect the spring on all my petrols, but I also use a good quality digital servo, it's surprising how much of a difference a good servo on the throttle makes, i disconnect the spring as if the servo is fighting it it will draw a lot more current out of the flight battery's, and I've seen servos burnt out because of it woody Quote Link to comment Share on other sites More sharing options...
Ultymate Posted April 20, 2014 Share Posted April 20, 2014 Any good servo should cope easily with the load imposed by a throttle spring. If not they have no chance of coping with the loads imposed by flight surfaces in the air and the amp draw is minimal and will be of no consequence if the models properly equipped with adequate batteries. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted April 20, 2014 Share Posted April 20, 2014 As an observation my MVVS 50, which has a Walbro carby by the way, the manual expressly says not to do away with the spring otherwise wear will occur as other posters have mentioned and described. As Ultymate says the best option is to put a decent servo and linkage on and take the time to fine tune the throw via the TX, which I find is time well spent for a reliable engine run. Quote Link to comment Share on other sites More sharing options...
Rich too Posted April 20, 2014 Author Share Posted April 20, 2014 Thanks guys. I tend to agree with Ultymate, having read a few threads. The problem with servos appears to stem from the fact that given no resistance, people tend to go for a cheap servo on the throttle (i'm guilty of that in the past), so i'll put a decent servo on there and leave the spring. I have already experienced poor idle on a Zenoah and want to avoid that. I'll monitor battery usage.... Rich Quote Link to comment Share on other sites More sharing options...
Mac Duberia Posted October 25, 2014 Share Posted October 25, 2014 Hi all, Just a quick question on a dle35 ra, would I have an issue running the engine if I turned the carb 180 degrees, this is purely because the throttle control rod can have a straight run from the servo arm. Any thoughts? Mac Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 27, 2014 Share Posted October 27, 2014 Do leave the spring on and connected . As already said should the linkage fail then it a fail safe to idle or engine stop . If its removed or disconnected then the butterfly can vibrate causing the spindle to wear in turn causing air air leaks and poor idle . Never had any problems with servos handling the spring pressure either ,just use a decent servo and not mini servo as the vibes will kill the gears in no time . The old 148 or similar are fine for this and hold well without scoffing all the battery power. Re turning the carb 180 deg . Usually not a problem but do make sure any holes in the insulator or gasket line up you will also have to turn the insulator block as well . Some engines use drillings to allow crankcase pressure to work the diaphragm pump while others have a short length of tubing from a crankcase nipple to the carb . I regularly change mine round without any problems . Quote Link to comment Share on other sites More sharing options...
Mac Duberia Posted October 27, 2014 Share Posted October 27, 2014 Thanks for the reply but can you clarify what the insulator block is...- is it the black block that is between the engine and the carb? so when I undid the two hex screws the whole carb and the black block came off as one and I turned it 180 and screwed it back on. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted October 27, 2014 Share Posted October 27, 2014 That's correct the black plastic spacer is the insulator block .If it stuck to the carb that's fine and all the air passages should line up fine. Quote Link to comment Share on other sites More sharing options...
Mac Duberia Posted October 27, 2014 Share Posted October 27, 2014 Ok thanks for your time and giving me the confidence. Mac Quote Link to comment Share on other sites More sharing options...
Andrew Cousins Posted November 16, 2016 Share Posted November 16, 2016 Guys just been reading through this thread. I am thinking of converting to petrol. One thing I am always concerned with is battery current consumption. I always go to great lengths to ensure free movement of surfaces to reduce drain on the battery. Now disconnecting the return spring on the throttle makes sense to me. I understand the safety side of it, engine returning to idle if linkage fails but what about large glow engines they don't have return springs. So I have a question. DO we have any evidence that disconnecting the return spring but leaving it fitted to stop the butterfly valve shaft wear have any performance issues. Thanks Quote Link to comment Share on other sites More sharing options...
Rich too Posted November 16, 2016 Author Share Posted November 16, 2016 I don't understand the question! What performance issues? The spring does nothing apart from return to idle. I would not be concerned with battery drain - I've never had problems leaving the springs attached. And the load on flying surfaces would mostly be aerodynamic rather than from the hinges. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 16, 2016 Share Posted November 16, 2016 Leave the spring on Quote Link to comment Share on other sites More sharing options...
Andrew Cousins Posted November 16, 2016 Share Posted November 16, 2016 The original post alluded to tick over issues. Quote Link to comment Share on other sites More sharing options...
Rich too Posted November 16, 2016 Author Share Posted November 16, 2016 Well, yes then, I had issues with the performance hence the original post. I always leave them connected now and have not had problems. However, others disconnect them and do not have issues. I suspect that they are better at setting up the throttle linkage than I am! Quote Link to comment Share on other sites More sharing options...
Andrew Cousins Posted November 16, 2016 Share Posted November 16, 2016 ok so the jury is out on spring on or spring off. As I am a newbie I will go with the spring on. Just a thought what about lengthening the throttle arm on the carb to give better leverage this will reduce the strain on the servo and reduce the current drain. Just a thought. Are there any other words of wisdom or nuggets of information that a petrol newbie should take heed. Many Thanks Quote Link to comment Share on other sites More sharing options...
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