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JD Miller · 03-29-2011, 02:38 PM

I have a Marvel-Schebler on my 1931 sedan. The carburetor has been on the car and in service since 1949. Never a problem. Better performance than most Zenith carbs I see in operation.

For starting, when cold weather, that would be up to 40 or so degrees, the GAV is opened a full to 1 1/2 turns open. Once started the GAV is gradually reduced till it is open 3/4 to 1 turn. In warm weather, above 40 degrees then the GAV is usually opened 3/4 turn.

Once the engine is warmed up the GAV is closed for idle when the spark is fully retarded. Advance the spark and the GAV is opened about 3/4 turn. On the road at any speed the GAV is usually run at around 1/4 to 1/2 turn open.

Gas mileage stays around 17 mpg no matter what the average road speed may be up to 55 mph.

I would not consider any carb other than the Marvel-Schebler. Have tried rebuilt Zenith carbs and Tillison. Neither of these carburetors can come close to the performance of the M-S.

03-29-2011, 02:38 PM	#12
JD Miller Senior Member Join Date: Jul 2010 Location: Yorktown, VA Posts: 139	Re: Marvel Carb Adjustments? I have a Marvel-Schebler on my 1931 sedan. The carburetor has been on the car and in service since 1949. Never a problem. Better performance than most Zenith carbs I see in operation. For starting, when cold weather, that would be up to 40 or so degrees, the GAV is opened a full to 1 1/2 turns open. Once started the GAV is gradually reduced till it is open 3/4 to 1 turn. In warm weather, above 40 degrees then the GAV is usually opened 3/4 turn. Once the engine is warmed up the GAV is closed for idle when the spark is fully retarded. Advance the spark and the GAV is opened about 3/4 turn. On the road at any speed the GAV is usually run at around 1/4 to 1/2 turn open. Gas mileage stays around 17 mpg no matter what the average road speed may be up to 55 mph. I would not consider any carb other than the Marvel-Schebler. Have tried rebuilt Zenith carbs and Tillison. Neither of these carburetors can come close to the performance of the M-S.