"I have an XGK Mk 1 from the 1970's (which I bought from E-bay) and it has a far better metal and composite pump, rather than the modern whisperlite. I have since then got rid of the whisperlite due to its easy blocking rubbishy shaker jet operation. The XGK Mk 1 will run on anything! AVGAS and all other aviation fuels (I'm a glider pilot), Maritime, Diesel, 2 Stroke chainsaw fuel, Diesel, White Gas, White Spirit, paint thinners to name but a few.
Why MSR did you have to stop using a Composite & metal pump, for the rubbish you produce now?!"