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SU H-type Rebuild Kits

Last post 11-03-2007, 7:28 AM by TechTipAdmin@Moss. 0 replies.
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  •  11-03-2007, 7:28 AM 10973

    SU H-type Rebuild Kits

    Carb Rebuild Kit Installation
    Robert Koval
    Westmont, NJ

    After installing a re-build kit in an SU carburetor (especially an H-series) it is sometimes impossible to achieve a sufficiently lean mixture by manipulation of the mixture adjusting nut alone. Before resorting to the quick and make-shift solution of lowering the needle in the piston, examine these sketches carefully and compare the actual carburetor to them.
    The proper solution may be effected through careful installation and assembly technique. The cork seal, located between the carburetor body and the cupped aluminum washer must be spongy and pliable so that it "cold flows" into the cup of the washer as the securing nut is tightened. When properly assembled, only a thin line of cork (0.5 mm) will be visible between the carburetor body and the top edge of the aluminum cupped washer as shown in the illustration.

    Assembly in accordance with fig. 3 will insure that the mixture adjusting nut will provide enough jet travel to set the fuel/air mixture as lean as required while keeping the needle at its specified position in the piston.

    Since the metal of the carburetor body is soft, do not, in your enthusiasm to squish the cork seal to its proper dimension, over-tighten the securing nut! Soak the cork seal in light oil (a day or two if possible) prior to assembly. The oil soak will make the cork seal pliable for easy assembly.


    Working on automobiles is inherently dangerous. Moss Motors, Ltd. is not liable for injury or damage due to incorrect installation or use of their products. All products are sold with the understanding that the safe and proper installation and use of the products is the customer’s responsibility. Follow factory workshop manual procedures and instructions, but use current shop safety standards and common sense. Some tasks will require professional advice or services which Moss Motors cannot provide.

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