Note: Picture to be used for reference only. Carburetor models may vary.

Note: Please read all the WARNINGS below. 


a) Use the small screwdriver or pliers to unhook the spring (33) from the accelerator pump lever (34). Disconnect the accelerator pump rod (3) from the ball sockets at each end. Disconnect the choke valve tension spring (14) using the pliers, and remove the choke lever fulcrum screw (1). Remove the five airhorn screws (31) and their lock washers. Lift the airhorn (32) off, with the accelerator pump attached.

b) Remove the small cotter (split) pin from the top of the accelerator pump, then remove the accelerator pump lever screw (35) to release the lever from the airhorn. Now you can unhook the accelerator pump and release it down through the casting.

c) Remove the power valve (28) and its ring gasket (29) from the bottom of the accelerator pump well. We recommend the use of a wide, flat blade screwdriver with a slot cut in the the blade to clear the delicate pin in the top of the power valve. Failure to use a correct tool may result in damage to the power valve and poor performance. Place the new gasket on the new power valve and fix the power valve back into the casting using your special screwdriver. Do not over- tighten.

d) Install the accelerator pump (10), back into the bowl casting taking care not to wrinkle the leather seal or catch it on the slot in the pump well. This is not a simple task with a used pump as the leather swells in use, but it can be achieved with care and perseverance! And it is far easier when removed from the airhorn.

e) Place a new airhorn gasket (20) in the correct position on the bowl casting, and slide the airhorn back on, inserting the top of the accelerator pump through the correct hole in the airhorn as you do so. Now fasten the airhorn down with the five lock washers and screws to 5in/lb torque. Install parts 7 to 2 in reverse numerical order, remembering to re-attach the two springs. Now attach the accelerator pump rod (3).

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 –