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

Note: Please read all the WARNINGS below. 

NOTE: Stromberg main jets can usually only be accessed with the carburetor removed from the intake manifold. However, if you are experienced with Stromberg service and repair, an alternative is to disconnect the carburetor bowl and airhorn, leaving the base casting in place on the manifold. This is sometimes preferable if you have multiple carburetors as you can leave the linkage in place.


a) Remove the two metering jet plugs (the two outer ones – 48) and their gaskets (44) from beneath the float bowl to expose the main metering jets. Leave the center plug in place.

b) Remove the main jets (47) from the casting using a Stromberg Premium Jet Wrench (Part 9071K). Wind the two jets out counter-clockwise. If they are tight, DO NOT use excessive force or add an extension bar to the jet wrench. Replace the plugs and soak the jets in penetrating oil (it will work via the holes in the bottom of the float bowl)

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 (or the use of excessive force) could result in damage to the jet and poor performance.

c) Insert a new main jet (47)  into the Stromberg jet wrench and carefully screw it into the casting, checking that it turns freely and is not cross-threaded. The threads are easily damaged! Then repeat for the other main jet. They must fit snugly against the emulsion tubes (46), but not apply any force against it. Fit a new ring gasket (44) to each metering jet plug (48) and install them back into the casting. Packs of 10 new ring gaskets (9564K) are available from your Genuine Stromberg dealer.

CAUTION: Do NOT over-tighten the main jets. Over-tightening can crush the small metering holes in the emulsion tube. 

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 –