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GGT15 Mixture Screw Initial Setting

Old 02-29-2020, 05:43 PM
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TaiAir
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Unhappy GGT15 Mixture Screw Initial Setting

Hi, a complete newb here. I have purchased a GGT15 which I have installed on a Kyosho Calmato D low wing trainer. I have not been happy with how the engine runs, seems to be losing power after flying for a bit (I have about 10 hours on the engine) and I am concerned that it is running lean. I live in a foreign country and even though I can speak some of the native language I don;t have a great commend of it. The people who fly at the club with me a great and very helpful, but i think in this instance they have been trying to set the mixture on the engine as if it was a nitro engine and not as per the manual. So I want to go back to original settings on the carb and just do it myself. This is where the problem starts, The manual states as Step 1 in restoring the Mixture Control Valve to the original setting I need to "Open the mixture control valve (MCV) one turn (360 degrees)". But open one turn from where? If the throttle is open and I try to close the MCV all the way it simply runs out of thread and fully screws into the venturi. Obviously it cannot be open 360 degrees from fully open, so from where is the MCV opened 1 turn from? I have at the moment assumed that I close the throttle body fully and hold it firmly in that position, then screw the MCV in until I feel hard resistance with the screw driver and from that position I screw it out 1 turn. For the life of me though, when I do this and then follow the other steps I do not feel any resistance when opening from fully closed, This thing is really well machined and is SMOOTH, but I again am assuming that they mean it is sticking a little bit at the closed position. I get the feeling there is a taper in this assembly somewhere and that I am trying o find a position on this taper where everything is tight at fully closed but will still allow fuel to flow when opened slightly. I hope to get this engine running smoothly and for when I do I have learnt how to tell my friends thank you for your offer of help but leave my damn engine alone!
Thanks in advance for any advice or pointers you can provide.
Old 05-04-2020, 02:41 PM
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bklambdin
 
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I'd like to know this too.
I've got a new GGT15 and don't know where to set back to factory defaults for the needles.
On a nitro, it's like 1.5 turns out from closed, and the mixture screw is level with the surrounding body.
How is this thing set?
Old 05-04-2020, 05:38 PM
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TaiAir
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It took a while for me to work it out but I got there in the end. The very first thing you need to do is completely disregard everything you know and have learnt about nitro engines because it means nothing with this engine and to tune it like a nitro engine will only end in disaster. I put hours into reading the manual to try and understand the process of resetting it to factory settings and how to tune it. The info is all there in the manual, and even though it sounds strange you just have to have faith. There was a key part missing in the manual regarding resetting the low speed jet (mixture control valve) at that was what is the initial position of it? Page 3, Item 3 of the manual it states to open the valve from one turn, but if you have been fiddling with it do you just open it one turn regardless? The answer is yes. Just open the mixture control valve 1 turn and then follow the rest of the procedure exactly as documented. It is VERY fiddly and takes some time but it can be done. You will need to disconnect your throttle from the servo so you can feel the resistance they talk of with you finger tips as you open and close the throttle. The resistance is very very light and takes a fine touch to feel it. After you have done this you can then follow the instructions on Page 3, Item 2 for how to set both the mixture control valve to achieve a smooth idle. Setting the mixture control valve for idle is really fiddly as well, but it is achievable, and again you just have to forget what you know and follow the manual. Then as crazy as it seems you follow the instructions on Page 3, Item 1, in order to set the needle valve. I have no idea why the manufacturer chose to write these steps in what appears to be a backwards order, but once you work it out it is achievable. You just have to accept that it is not a nitro engine, there are no short cuts to setting it up, and that the manual is actually your best friend. I haven't got many hours on mine yet, but I have heard that once you set this thing up it is pretty much set and forget with only having to go back for minor adjustments at the change of seasons. I have also noted that it should never be run lean as it will just stop without warning when it gets too hot and that clean fuel is an absolute must. Hope this is of some help to you, happy flying.
Old 05-05-2020, 03:29 PM
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bklambdin
 
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Thanks
Brian

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