wonwinglo

One of the most useful general purpose engines on the market,the MDS range is also probably the most mis-used and mis-understood,these reliable little powerplants are cheap and powerful,the reason many do not get the best from any glo motor is the way the carb is set up initially,dis-regard the manufacturers instructions that the carb is pre-set,impossible until a little running of the motor has taken place,follow these simple steps to get the best from your MDS carb,a little bit of tweaking can work wonders with reliability-
Note that these carbs have a secondary needle valve,this can be the cause of many problems if not set to the optimum position,firstly remove the main needle valve and give it a wipe,make sure that it is in good condition and not bent at the end,next screw this back in all the way and then back off anti-clockwise three whole turns,next attach a piece of plastic fuel pipe to the fuel inlet on the carb,place one finger over the carb intake and gently blow through the pipe,you should just be able to hear air hissing through,to check this quickly release your finger over the carb,as you place it you should feel a slight resistance,if you cannot blow freely through then there must be a blockage,rectify and then proceed to the next stage.
Now turn your attention to the secondary needle and note its position,it should be just slightly proud of the housing,if not take a small screwdriver and unwind slowly,MDS put a locking paste here so it could be difficult to shift,take care as it is made from brass and it is easy to do damage,now set your needle 3-4 turns out fully from fully closed,fill the tank with fuel and run the engine,get it running rich at full power with plenty of smoke and lift the model vertically into the air and hold it there for a few minutes,if the engines dies then open the needle half a turn at a time until it keeps running but there should be still plenty of smoke.
Now throttle back the motor fully and sharply open the throttle and note what happens,if it splutters and takes a while to pick up wind in the secondary valve a small amount until the response improves but do not overdo things,only a little at a time.
If the engine refuses to run smoothly then take the secondary needle the other way ie outwards and then compensate by turning the main needle inwards until the engine runs smoothly,now do your vertical check again and see what happens,you should soon find the best optimum position for both slow running and full power setting,however be warned that your idling will only improve with lots of running,the tapered bores of modern motors whilst giving long life does mean we need to make sacrifices on the engine idle during the engines early life,just run the motor a little rich to compensate,best way is to clear the engine with short bursts of power during the flight,say in the circuit just before landing.
With a little bit of care you should be able to get your MDS running like silk,I have lots of these engines and they certainly give me good service.
One other tip is to replace the rubber o-ring at the base of the carb every seasons flying and to make sure that it is fully seated at the base of the carb,do not be tempted to add another seal above the lip,it does not work !

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'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
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