A DIRTY MUFFLER

Shannon News, 4 June 1929, Page 4

A DIRTY MUFFLER

Although the average motor driver does not realise it, carbon formation in the muffler, if allowed to become excessive, w r ill send up the petrol bill and cause bad high-speed running. A case that came under notice recently was on a popular light American car. The engine in this car would run well at low speeds, but once the speed was raised to the 35 mark the engine would slow down, and step in a short while, as though out of petrol. After the carburettor had been taken apart and cleaned, the valves ground and re-seat-ed, and the valve-timing checked, without noting any improvement, the trouble was finally found to bo in the muffler, which had only small openings for the exit of the exhaust gases. These were partially closed by an accumulation of carbon, which caused back pressure. At low speeds the gas had sufficient time to pass through the small openings, but at high speed the gas was forced into the muffler quicker than it could got out. As soon as the muffler was cleaned the engine functioned as when new.