alsfarms

Updraft Stromberg SF-3 or 4 Carburetor wanted

Recommended Posts

I am looking for a Stromberg SF-3 or 4 up draft carb. for a current project.  It needs to have a 1-3/4" or slightly larger bore and an accelerator pump.  Please drop a note if you have such a carburetor. 

Thanks,

Al

Share this post


Link to post
Share on other sites

Hello Jon,  Do both carbs. have  the provision for the accelerator pump?  I had mis-understood information on these Stromberg carbs.  I had thought that each series would have a variety of throat sizes.  I am now guessing that the variable aspect of the SF-3 is in the jet sizes.  The problem I have with the SF-4 is it is a larger and different design than the SF-3.

Al

Share this post


Link to post
Share on other sites

Hello Jon,  Here are the numbers from a Stromberg SF-4 carb.  Can you tell if it has the accelerator pump from these numbers?  Outer circle 2CF37, inner circle 2474E.

Regards,

Alan

Share this post


Link to post
Share on other sites

Alan - this link will explain the bore or "throat" size, and also the internal venturi sizes:

 

http://www.thecarburetorshop.com/Stromberg_SF_carburetors.htm

 

Note that some SF-4's do have accelerator pumps, others do not.

 

The numbers from your tag don't seem to show up in the Stromberg literature.

 

The best way to get a feeling for if a specific carburetor has or doesn't have an accelerator pump, is to look for the presence of the pump adjustment screw. Go back to the link, and scroll down to the pictured SF-4 carburetor. In the upper left corner of the picture is a long vertical 10x24 fillister headed screw. This screw is the pump adjustment screw. By varying the depth (adjustment) on this screw, one can vary the length of the pump stroke, thus saving gasoline?????:P

 

The carbs without an accelerator pump will not have the screw, rather just a short headless brass plug in the machined hole.

 

And the variable aspect, using your words, is in the internal venturi size. The physical size (SF-4) is the external size. The venturi size determines airflow. And the jetting is selected to correspond to the airflow.

 

Jon.

Share this post


Link to post
Share on other sites

I have an SF-4 Stromberg for sale in excellent shape. Doesn't look as if ever installed. Screws look as untouched. I will post some Pic later. I have had it for sale a couple years ago on this site.

Harold

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now