Note: Picture to be used for reference only. Carburetor models may vary.
Note: Please read all the WARNINGS below.
a) Remove the two metering jet plugs (48) with their gaskets (44) from beneath the float bowl, exposing the main metering jets. Leave the center plug in place.
b) Remove the main jets (47) from the casting using a Genuine Stromberg jet wrench (Stromberg Part 9071K). Wind the jets out counter-clockwise.
CAUTION! Stromberg main jets should only be removed and installed with a correct Stromberg jet wrench designed for this express purpose. Failure to use the correct wrench could result in damage to the jet and poor performance.
c) The emulsion tubes (46) are only held in by the main jets, but may be gummed up with old gasoline deposits. If they are reluctant, a little releasing fluid will help. Do NOT force them. Be patient! DO NOT tap the angled point at the top end. If they pop out, move to step f). If you get no luck with releasing fluid, you’ll need to remove the airhorn (32), so continue to step d).
d) Disconnect the accelerator pump rod (3) from the ball sockets at each end. Remove the choke lever fulcrum screw (1) and disconnect the choke valve tension spring (14). Remove the five airhorn screws (31) and their lock washers. Remove the airhorn (32) taking the accelerator pump (10) with it and lift off the airhorn gasket (20).
e) Insert a # 6 X 32tpi tap into a pin vice handle and screw it into the lower end of the emulsion tube with 3 or 4 turns. Leave the tap in the tube. Then insert a 2.5 to 3 inch piece of piano wire (or thin tool steel) that will slip, without binding, into the top end of the emulsion tube (ie. 3/32”), so it bottoms out against the end of the 6×32 tap inside the tube. Take a light hammer and give it a firm tap from the top to pop the tube out through the bottom of the casting.
f) After ensuring that the emulsion tube cavities are clean and clear, drop the new tubes in from the bottom, with the long end of the slash cut uppermost. The two flat sides at the bottom of each emulsion tube must fit into corresponding flats in the bowl casting bore to prevent it rotating out of alignment. When properly installed, the tube should sit against a shoulder at the top end of the cavity. Give it a very light tap to check it is firmly seated. At the top, it will stick out into the booster venturi about 1/8 inch length.
g) Now, using a Stromberg jet wrench (Part 9071K), screw each main jet (47) back into place, checking that it turns freely and is not cross- threaded in the casting. The threads are easily damaged! Ensure they fit snugly against the emulsion tubes. Fit one new gasket (44) to each metering jet plug (47) and install them back into the casting.
CAUTION! Do NOT over-tighten the main jets. Over-tightening can crush the small metering jet holes in the emulsion tube. And when replacing other parts, do not over-tighten screws and other threaded parts which could damage the carburetor castings.
h) Place a new airhorn gasket (20) on top of the bowl casting (23). Fit the airhorn (32), carefully inserting the accelerator pump (10) into place, taking care not to wrinkle the leather seal or catch it on the slot in the pump well. Fix the five lock washers and airhorn screws (31) (to 5 in./lbs. torque). Attach the choke lever fulcrum screw (1), taking car not to pinch the choke shaft end lever (51). Connect the choke valve tension spring (14) and attach the accelerator pump rod (3). You may find it easier to fix the top end first. Manually operate the throttle lever and choke mechanism, checking for sticking, binding, ‘over-center’ movement, or malfunction.
You’re done! If you think we’ve missed anything or we could improve on this Genuine Stromberg ‘How To’, please let us know. Email – firstname.lastname@example.org