Even if you regularly use your classic, it isn’t in daily use. Modern fuel goes stale very quickly when exposed to the atmosphere and as your car sits in the garage what is left in the carbs and fuel lines either evaporates or runs back to the tank. That means that you have to churn over the engine for a prolonged period of time before fresh fuel is pumped up from the tank and eventually into the cylinders. Depending on how powerful your mechanical fuel pump is and how good your starter motor is it can take up to a minute just to get enough new fuel into the engine so it can burst into life.  But it gets worse!  This very quickly runs your battery flat, puts unnecessary stress on the starter motor and pulls massive electrical loads through your starter wiring.

Further to the starting issues mechanical fuel pumps run off engine speed, in theory the faster the engine is going, the more fuel is delivered. This was all well and good back in the mists of time, but modern fuel isn’t as volatile as it once was and the mechanical pump fuel delivery isn’t as consistent as it could be. The simple fact is that your engine hasn’t got the amount of fuel it needs at the right time.