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Aaargh! Motor won't idle! Grrr.

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I am having problems with my Solo 210 motor with Bing 84 carb, and I hope you can help. It idles really rough and floods very easily. When I start it, it runs quite rough and the idle is slow even when I screw the idle screw (the big screw) in. If I turn the mixture screw (the small one) it seems to have no effect on the idle speed. It will rev up to full power and take off alright, but then it runs a bit rough below about 1/3 throttle. When I flew it yesterday I found that at 1/3 throttle it would run ‘lumpy’ - it is hard to hold it at constant revs. Full-power is fine, but anything below about 1/3 is hard to keep constant. Sometimes it will die right down to nearly cut out and then it will rev back up again.

If I leave the motor idling on its own it will idle at very low revs (below 900rpm) and then it will stop after about 10 seconds. The engine is then hard to restart (I think it is flooded) If I then take the spark plug out it is covered in oil. But if I take off straight away, the motor will run fairly well and then the spark plug is a light brown colour with no oil.

I have checked that there are no air leaks around the hose that joins the engine to the carburettor, and also I have given the carburettor a really thorough clean to ensure there is nothing blocking the idle jet.

Any ideas? Please help!

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Tom you could try moving the clip on the carb needle down to the second position.

This will allow more fuel flow at low revs and you should then be able to control the idle with the large screw.

FB say to idle it quite fast at 2600.



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hi tom

why did you replace the floats tom thats not a common thing to do

unless there not air tight . you would set the float hight by a mesurment

from the gasket face were the bowl mates to bottom of carb . mesurments

differ , easy if you take carb off , turn it upside down . floats will/should close

take a reading from gasket face to centre of floats . could be dfferent on your bing so check first .

also as said before the clip on the needle ' the nearer the top the leaner it is

hope this might help

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Thanks again for all the advice.

A little update from the shed...

I swapped the flexible hose back to the original stiffer one, moved the needle up to the second notch, and screwed the idle screw right in, and finally managed a smoothish idle of around 1700rpm. Hooray! Will fly on Thursday evening if the weather forecast is correct, and see how it is in the air. Fingers crossed...

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  • 2 weeks later...

A little update for anybody who it may help (those with a Bing carb)...

I ordered a new slide needle and clip from Fresh Breeze. I fitted it this evening and when I compared it with the old one it was in much much better condition. The old one was very worn. So I fitted the new one in the top notch (as advised by FB), fitted a new spark plug and cap, and hey presto, a motor that ran like a dream. :D

So I battled a takeoff wading through waist-deep grass (the farmer cut the one next door but hasn't done my takeoff field yet) and had a wonderful fly. And the Small size Sky Anakis that I just bought was great fun!


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