carbking

Stromberg series SF and SFM updraft carburetors

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I am often asked "what newer replacement carburetor can I put on my older vehicle?".

 

While there are a number of different brands, series, and qualities of replacement carburetors; in my opinion (others will obviously have different opinions), the Stromberg SF and SFM (marine) series are at the very top of any list. My opinion was shared back in the day by many vehicle manufacturers, as after the introduction of the Stromberg SF series in 1932, MANY manufacturers asked Stromberg to offer specific replacements for their older vehicles. But Stromberg also offered all sizes of the SF and SFM series as universal carburetors with adjustable main metering jets and clamp-style throttle arms so the carburetors could be easily adapted to many different vehicles (the KEY is to choose the carb with the proper size internal venturi). The Stromberg SF/SFM series were not discontinued until 1968. From 1932 to 1968 is a pretty good run for any product in a field changing as fast as the automobile changed in that time period.

 

To assist the enthusiast, I have produced an article, much of the information taken from original Stromberg documents of which I am the present caretaker. The link to the article is:  http://www.thecarburetorshop.com/Stromberg_SF_carburetors.htm

 

Others will bring up the popular Carter BB-1 aftermarket carburetor which in of itself is a very good carburetor. However, the single venturi and the mechanical accelerator pump of the BB-1, at least to me, make it less desirable than the Stromberg.

 

Jon.

Edited by carbking (see edit history)
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I'll second that , Moe ! Sentiments shared by all I am sure ! His Majesty Rules ! Thank you , Jon , you are the greatest ! A mere subject in the realm ,  old Carl

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I have updated the article to include pictures of the larger carbs (SF-4 and SF-5) plus some published CFM ratings by Zenith, which at the time was a sister company to Stromberg. The ratings are applicable to the Stromberg carbs.

 

Jon.

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On ‎9‎/‎17‎/‎2016 at 12:51 PM, carbking said:

Others will bring up the popular Carter BB-1 aftermarket carburetor which in of itself is a very good carburetor. However, the single venturi and the mechanical accelerator pump of the BB-1, at least to me, make it less desirable than the Stromberg.

 

Not sure everybody understands the problem with mechanical accelerator pump on an updraft carburetor.  When you pump the accelerator on an updraft with mechanical accelerator pump and the engine is not running, the fuel runs out of the carburetor..everywhere.  On a downdraft it is not a problem, the raw fuel goes down the intake.  I still run BB1 Carter carbs, I only start them with the choke, works great every time (from your advice, thank you).

 

The cost of the BB1 vs. the Stromberg alone should be enough to carefully consider the Stromberg (better get one soon before the prices go up)  Next time I need one I will be looking at Stromberg's

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The down side to that is,  it's easy to flood the motor with raw fuel when starting if you pump the pedal too much on a downdraft. Many updrafts have a drain hole - like Jon mentioned - in the base of the  carb right below the venturi and the main discharge jet. It's less likely to flood the motor with raw fuel.

 

Paul

Edited by PFitz (see edit history)

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I have a Dodge 8 1930. It LOVES petrol but if I put my foot on the accelerator when starting, it is very hard to start. I use a touch of hand throttle and the choke if necessary (which generally gets pushed in fairly soon at the same time as a bit more hand throttle is added). While it likes petrol it doesn't like being drowned in it! The foot takes over once it is running evenly.

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