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Malta: Self lengthening carburettor needle valve

Yammi123

New member
Hello

Now I post in Boat Repair Forum at Marine Engine, because probably there I’ll find more engine experts, as the forum for boats. Maybe someone here could support me. Anyway: Thank you in advance.

The problem area: The needle valve controlling the fuel float into the carb chamber (sorry for my English – I don’t know the exact word: is it a carburettor needle valve?) of my two-stroke engine (known as Yamaha 6L5 –L or 3HK MALTA) consists of 2 pieces: an aluminium part (about 4 mm outer-diameter) and a plastic end-piece comparable to a mushroom. In the aluminium part is a blind hole of about 2 mm diameter and the “mushroom” has been put into this hole. The plastic part is one opposite needl-side of the valve. The shaft of the "mushroom" is shorter than the length of the hole. It remains a small cavity remains of about 5 x 2 mm.

The problem: In the course of some operating time (some months) fuel enters the cavity. Perhaps due to vibration or "micro-pumping action" and extends the size of the valve-needle about 1-2 mm. The float needle valve will be longer, with all its consequences ... The dealer knows no advice

Current work around: I pull out the mushroom, the empty 1-2 drops of fuel and reassemble the two parts. Then the float needle valve its original length and the swimmer is again in horizontal position.

Does anyone know the problem and a permanent solution?
 
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