Is Brian's carburetor float a sinker of a floater?

Dear Car Talk

Dear Car Talk | Aug 01, 1989

Dear Tom and Ray:

I have a 1959 MGA 1600 with twin SU carbs. The engine is kept in perfect tune (or as perfect as a British engine can get) yet I've had one problem for a year and a half. If the car is allowed to idle too long, or after prolonged city driving, the engine will start to sputter and I'll have to blow it out with high revving for a minute or so. Any ideas?

TOM: The technology of your carburetor is pretty simple. Go into your office, Brian. Lift the top off of the white porcelain fixture in the corner. You see the float? That float shuts off the water when it reaches a certain level. You have the same sort of floats in the carburetors of your MGA.

RAY: Like matzoh balls, carburetor floats come in two varieties... sinkers and floaters. Yours are sinkers. I don't know if you have metal or plastic floats, but both become porous when they get old. If they don't float and cut off the gas flow, too much fuel rushes into the carburetor, and the engine floods. When you "blow it out" at high revs, you are burning the excess fuel. New floats should fix this. And if you want floaters in the future, Brian, beat the egg whites separately and give those things plenty of room to expand while they cook.

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