Tonight, I pulled the fuel pump out and verified that it would not turn under power and that I could not turn the impeller through the intake port with small sharp tool. I shook it firmly and got small chunks of hard black stuff out of it. With nothing left to lose, I disassembled the pump and found that about 1/3 of the vanes on the impeller were broken off. I pulled the impeller off the motor shaft and washed the bits and pieces out of the pump. I reassembled it (it still amazes me how often I use my anvil in motorcycle work. I used it to make some muffler brackets for Toni’s trike Tuesday night) and reinstalled it, with a filter this time. I also put the valves on the feed and return lines. I fired up the pump and even using a funnel to try to prime it, it would spin but not flow any fuel. I suspect that, while the impeller is badly damaged, it could probably still move fuel. Most likely, the check valve or the body of the pump is clogged with impeller vane bones or perhaps the original debris that destroyed the pump.

I have found several suitable pumps on eBay. Just waiting on the first auction to end

I looked into connecting the Honda tilt switch, but it will need a little bit of electronics to work. The tilt switch is open in the normal upright position and “closes” to 23K ohms when tilted. A single transistor and a resistor or two is all that will be needed to connect it.

In the mean time, I’ll be updating the wiring diagrams and impatiently awaiting the new pump.