a fuel-injected engine, ignoring the throttle (no fuel) while starting permits electronic logic systems to produce the correct fuel mixture, often based on exhaust gases. Some fuel injection computers interpret "pumping" the throttle to indicate a flooded engine, and alter the fuel-air mixture accordingly. In a carbureted engine equipped with an accelerator pump (which advances fuel flow to match air ingestion under rapid throttle acceleration), "pumping" the throttle will force excess fuel into the engine, further flooding it. In worst cases, the excess fuel can foul spark plugs, sometimes necessitating their cleaning or replacement before the engine will start. This is most likely to occur on a carbureted engine in cold weather, after a running engine has been shut off briefly before being restarted. Doing so can cause the choke valve to configure the mixture for a cold engine start, despite higher actual temperatures, resulting in an overly rich mixture and flooded engine. See also Vapor lock References Engine problems