Up until 24 hours ago I was prepping for a two week trip to Florida to get some sun and thaw out. That's now on hold for the next few days. No problem except that I cleaned the garage and packed up the glacier of stuff so DW could use the garage while I'm gone. I don't want to make more debris so I'm going to work on the fuel tank mount and work out a few problems on paper.
To that end, I believe I've figured out a clutch for driving a hydraulic pump. As my recent starting problems taught me, the starter generator doesn't have the steam to overcome much more than engine compression so dragging a hydraulic pump at minus 10 degrees is probably out of the question. I considered using the mower clutch, but it's just too big, too large pulley size and, well, mine is pretty much a basket full of ground up metal anyway. I'm going to try installing a go kart centrifugal clutch keyed to the crankshaft with a double-row chain connection to the hydraulic pump. A bit of research has shown me a few offerings with different spring/flyweight options that will get me down into the 650-700 rpm engagement I'm after. I'd like it to fully engage at or below engine idle of 800 rpms, but that is much higher than the engine cranking speed so no-load starts should be easy. Clutches are available for most any hp rating up to 50 horsepower so it will be easy to source a solid unit with adjustable engagement.
That's the plan. As the engineer said while standing next to the smoking hole in the ground:
"Well......that should have worked....."