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Very interesting thread, especially the issue of hitting the boost pump to keep the engine from faltering immediately after start-up. And Ken's point about potentially causing cracks on the cylinder heads is worth pursuing.
With my background and location (at left) I know a little about this. I find that I need to hit the boost pump to keep the engine from dying after a hot start (typically after a 10-minute stop, whether at Customs or to refuel or to pick up passengers, in 90 degree weather). I had been under the impression that the principal purpose of the boost pump is really to get the right amount of fuel into the fuel injection system by pushing fuel past vapor locks which occurs on the fuel lines near the hot engine.
If my impression is correct and if you hit the boost pump for only a second or so (Kevin calls it a "blip"), turning it off as soon as the engine starts recovering, then I don't think you're pushing cold fuel into the chambers. For two reasons. First, the fuel that the boost pump is pushing into the chambers is the fuel in the lines near the hot engine (yes, there may be some vapor bubbles, but there is also fuel, and it's hot); in short, fuel from the tanks doesn't somehow somersault over the fuel in the lines near the engine. My second reason comes into play if I'm wrong about the lines having fuel inside them. Let's say the lines are essentially empty -- it's a huge vapor bubble inside. As long as the amount of fuel pushed by the boost pump is small (which comes from just blipping the pump), then when I look at the length of the fuel lines near the engines (hoses followed by thin tubes to the injectors), it seems to me that stretch of HOT fuel lines is going to warm the small amount of incoming fuel being pushed through.
I'm kind of out on a limb here. Sure would like for others to step in here and voice their opinion.
BTW, I'm a firm believer in Ken's last point, about leaning the engine on approach. I don't do it because of concerns of cold fuel into hot surfaces and cracking (and, to be honest, I don't quite understand the concern). I do it for a different reason: I'm concerned that I'll flood the relatively cool enginewith a full-rich mixture if I have to give it full throttle to go around. And it does require remembering that you have to push all levers forward simultaneously to accomplish full power.
Ernie
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