However, it may happen that such a course is impossible at the time and if the following instructions are carefully observed there will be no danger of seriously disturbing the efficiency of the instrument. As soon as possible after changing the level the Carburetor should be sent to a Zenith Station to have the level checked.
Needle Valve Adjustment
The only place any adjustment of the level should be attempted is at the Needle Valve Collar, its relative position on the Needle Valve determining the point of closing of the Valve. Remove
the Float Cover from the Carburetor, draw out the wire holding the Lever Weight Axles and remove the Needle Valve entirely from the cover.
Take a knife, or any sharp instrument, and mark around the Needle Valve at the lower side of the Collar in case it is found necessary to bring it back to this position. Scratch a mark on the Needle Valve 1/32" above the collar. provide a block of hard wood through which a hole slightly larger than the largest diameter of the Needle Valve has been drilled. Put the Needle Valve into this with the point down.
Now, with a flame soften the solder holding the Needle Valve Collar on the Valve, first wetting it with soldering acid or paste, and when the Valve is free in the Collar tap it down to the upper mark, or 1/32" . Allow it to cool, thus again setting the solder, and replace it in the Valve Cover. This will lower the level. If a further lowering is found necessary repeat the above but never go further than 1/32" at a time.
Next, replace the Cover on the Carburetor, press the Needle Valve down tight against its seat with the finger and mark a line around it at the upper edge of the boss on the Cover that takes the thread of the Dust Cap. Remove the Cover from the Carburetor and with the fingers bring the mark on the Valve back to the above position and see what position the Lever Weights are set. If they are not horizontal it means that you have gone too far, that the travel of the Valve will be insufficient, and that the Float mechanism will not function properly. This travel should not be less than 5/64".
To raise the level, move the Collar towards the point of the needle valve. Never bend the Lever Weights to change the level, and do not put additional gaskets under the Needle Valve.
Cleaning The Carburettor:
When there is water in the gasolene: a very few drops of water lodged in the bottom of the unions will suffice to produce transient difficulties in carburetion. Assuming the amount of
water to be very small, the trouble may be remedied by taking out the two hexagon nuts or plugs under the jets and the filter plug and emptying the Carburetor.
When Jets are |Choked With Impurities:
This is of frequent occurrence when there is no filter between the gasolene tank and the Carburetor; and sometimes even with a filter. A tiny speck of dirt etc., may partially clog the aperture of a jet, and though the engine continued to work, it does so imperfectly, giving indications of defective carburetion; popping, especially when picking up speeds etc.
The Jets can often be quickly cleaned out by closing the air strangler for a few seconds when running the motor fast. Take out the jets and remove any impurities found, taking care not to widen the apertures by using a cutting tool; clean out the Float Chamber, the pipes etc.