more float valve problems -- RESOLVED

This is a cheepie GY6 style 150CC carb -- a copy of a Keihin 24mm. New, the float needle had some crusty white corrosion which made it stick open. I touched up the needle with an emery board and that made it stick closed. I got a replacement needle and the bike ran well once. Today the valve is stuck open again. The bike has 150 miles and the inside of the carb does not look varnished.

So I am half tempted to just buy new carb if I could be sure of getting a half decent one. Otherwise I am looking for suggestions -- debris? scarring on the walls where the needle goes? bad Kharma?

Thanks!

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update -- resolved

The sides of the replacement needle valve looked worn after a week, in an even pattern opposite from the pointed end. The worn sections were hanging up, and also showing some of the same corrosion. I had a suspect -- bad gas. I drained the tank and fuel lines and replaced the fuel filter. I rinsed the tank out with a seafoam and gas mix several times I put a third needle valve in and it's been running fine for a couple weeks.

By the way I found a gas station with No Ethanol!

The day I rinsed out the tank and reassembled it was raining, so I just left a little gas in the tank in case something went wrong and I had to drain it again. The next day was clear and I went for a long test ride. You probably see the problem here. The symptoms of a float stuck closed are remarkably similar to that of running out of gas 8-(((

 

Re: more float valve problems

crappy aftermarket parts? Emery board is a bit harsh, kind of like sanding your carb slides with 400-grit (sorry Schooter.)

I would polish the needle valve and where it slides.

 

Re: more float valve problems

thanks fitz. yeah -- the corroded one was pretty bad. I shouldn't have tried to re-use it. I can try buffing the replacement, q-tips and jeweler's rouge? toothpaste? Hmmm, probably too harsh.

I just had a thought. Is it possible the fuel level is set too high? It ran for a short test drive the day I replaced the part. Today fuel is pouring out the overflow. I did not set the float height because I couldn't find a setting, but the two needle valves seemed identical in height.

 

Re: more float valve problems

Make sure the float moves freely on the pin, that is a often overlooked part of carb maintenance. I have had success polishing needle seats with a Q-tip and polishing compound.