The Ubiquitous Schebler Model D Carburetor

Richard A. Day Jr. of Leonardstown, Md., shares information about the Schebler Model D carburetor, possibly the most commonly-found carburetor for early twentieth-century marine engines.

| November/December 1999

  • Schebler Model D carburetor
    Richard's diagram of a Schebler Model D carburetor.

  • Schebler Model D carburetor

In my opinion the Schebler Model D carburetor was probably the most widely used of all the old time carburetors on marine engines. While Henry Ford made more than 15,000,000 carburetors for his Model T, not many of his carburetors seem to have been used on marine engines. A December 1921 article in Motor Boat it showed that 85 percent of the marine engine makers in the USA supplied Schebler as their standard offering.

It should be noted that there were a number of 'knock-offs' that were essentially Model D's. Michigan Wheel, Monarch Valve Company, Generator Valve Company, Acorn, etc., offered almost identical units to the Model D. Whether they had any agreements with Schebler regarding licenses, etc. is unknown. In any case none of them ever achieved the widespread use and production life of the Schebler Model D. It is my understanding that Schebler stopped making the Model D in the late 1930s, however, Canadian marine engine-makers such as Lunenburgh Foundry went on making them up until recent years. The highly polished finish on the Schebler Model D regrettably seems to have ended around the early 1930s. Currently available New Old Stock Model Ds from that period typically have a rough sand-cast finish.

There were a number of marine carburetor makers in the first third of the twentieth century. Most did not remain as marine carburetor makers, as the rapidly developing automobile industry was a much more attractive market. Kingston and Krice were two companies that made excellent marine carburetors, and most marine engine makers would supply a customer with the carburetor they preferred. On the other hand, large marine engine makers such as Ferro made their own carburetors. Other companies such as Belle Isle used a unique carburetor which was more like a float feed mixing valve than a carburetor. This unit was possibly of their own design. Belle Isle only lasted from 1908 until 1912, yet a few of their engines still survive, though most don't have their original carburetor.

The Schebler Model D

One point that needs to be made is that the typical small-boat marine engine that was in use up until the practice of converting automobile engines began to dominate the marine engine market really had very simple carburetor demands. For example, small-boat marine engines were operated basically at two speeds. Dead slow for docking and fishing, wide open throttle with the engine speed controlled by the size of the propeller for moving the boat at or close to its hull speed. With the widespread conversion of automotive engines to marine application, often the carburetor that applied to the automotive application became the carburetor of choice.

Of course the adoption of the automotive engine to marine propulsion brought with it its own set of problems. Not the least of which was the need for a reduction gear to match the high RPM of the engine to the low RPM of a propeller suitable for the heavy-displacement hull of the period.

The typical small, work-boat marine engine up until the 1930s turned between 400-700 RPM running from 1-1/2 HP in single-cylinder engines and up to 40 HP in four cylinder engines. This speed range was an excellent match for a propeller for hulls of the period. The typical small pleasure launch engine was one or two cylinders turning up to about 1000 RPM in the 1-6 horsepower range with a slightly smaller propeller. In any case, in either application the 2-speed operational limits would apply, therefore their carburetor demands were similar, air/fuel volume being the principal difference. The Schebler Model D met this requirement by making six different sizes. These were 1/2-, 3/4-, 1-, 1-1/4-, 1-1/2-, and 2-inch National Pipe Thread.

Joe Kieliszek
12/25/2010 7:34:37 PM

Correction on above, should be "2 and 4 cylinder Buick cars" Thanks again, Joe Kieliszek

Joe Kieliszek
12/25/2010 7:12:04 PM

Hello, The butterfly throttle version of the 1" Schebler D was used on many early 1 and 2 cylinder Buick cars. With internal modifications such as a venturi bushing insert, fuel pipe extension, Rochester float valve and seat as well as a brass float, these carbs can be used in place of more modern carbs substituted. The mixture needle still remains very touchey, but normally does not have to be adjusted again once set. The float level should be fairly high up in the bowl as to supply the engine adequate fuel for long hills... Thanks, Joe Kieliszek 1910 Buick Model "10" Toy Tonneau 1911 Buick Model 14B Runabout


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