I did some research and found that indeed did the pilots could help the engine by inserting a piece of metal... but that didnt really fix it. because for this 'fix' to work..they HAD to dive at full power, wich was not always what they wanted. It was only in the last 100 series merlin that they put in a direct injection fuel pump .
The 60-85 variants also had a fuel pump...but this one did not have enough power. The 100 variant was using the crackshaft speed.
Now...I do not know wich spit had exactly wich variant of merlin
.. but I think the mk2 was to early to benefit from the fuel pump variants
EDIT: this is what I found on wiki
the Merlin's lack of direct fuel injection meant that both Spitfires and Hurricanes were unable to pitch nose down into a steep dive. The contemporary Bf-109E, which had direct fuel injection, could "bunt" into a high-power dive to escape attack, leaving the pursuing aircraft behind because its fuel had been forced out of the carburettor's float chamber by the effects of negative g-force (g). RAF fighter pilots soon learned to "half-roll" their aircraft before diving to pursue their opponents.[25] "Miss Shilling's orifice",[nb 5] a holed diaphragm fitted across the float chambers, went some way towards curing the fuel starvation in a dive; however, at less than maximum power a "fuel rich" mixture still resulted. Another improvement was made by moving the fuel outlet from the bottom of the S.U. carburettor to exactly halfway up the side, which allowed the fuel to flow equally well under negative or positive g.[26]
Further improvements were introduced throughout the Merlin range: 1943 saw the introduction of a Bendix-Stromberg pressure carburettor that injected fuel at 5 pounds per square inch (0.34 bar) through a nozzle directly into the supercharger, and was fitted to Merlin 66, 70, 76, 77 and 85 variants. The final development, which was fitted to the 100-series Merlins, was an S.U. injection carburettor that injected fuel into the supercharger using a fuel pump driven as a function of crankshaft speed and engine pressures.[27]
still ... I dont know what aplies to wich spit