“Your impeller is likely seized by sediment. This is not a failure. This is the pump trying to tell you what it has carried for you. Clean it gently. Do not scrape. Listen. The sediment is your history.”
Ryo cleaned the impeller with a toothbrush. He replaced the O-rings with ones from a hardware store pack. He rewired the coil as best he could. Then he plugged it in, lowered the intake into a bucket of water, and flipped the switch. naniwa pump manual
Grind. Hiss. Chug.