Using A Manual Choke In Cold Weather
| Field | Cars |
| Went Obsolete | 1990s |
| Made Obsolete By | Automatic chokes, fuel injection |
| Knowledge Assumed | Basic driving skills |
| When useful | First few miles of driving from a cold start |
A car relies on the high-temperature of the engine to effectively burn fuel. When starting the engine from cold, the regular amount of fuel is not enough to deliver the required power.
The manual choke was a pull-out lever operated by the driver that opened decreased the carburettor's air-intake slightly, causing more fuel to be fed in and boosting power.
Leaving the choke closed for too long (once the engine had warmed up) resulted in an overly-rich mixture that made the engine stutter and stall. Opening the choke too soon would also stall the engine.
Modern cars use computers to work out exactly the right amount of fuel for each cylinder and injects that fuel automatically at precisely the right moment, making chokes thoroughly obsolete. The advancements came about (in Europe at least) because carburettor based engines could not meet emission targets.
Still of use to drivers of vintage cars. Also small carburated engines - snowblowers, snowmobiles, ATVs? motorcycles etc.