Following the diagram, Jake pulled the hose off the manifold. It was dry-rotted and cracked. A pinhole leak. The pump was fluttering weakly, getting only half the vacuum it needed. He replaced the hose, then, on a hunch, pulled the pump itself. He gently pried off the four tiny screws. Inside, the thin rubber diaphragm was stiff as cardboard, with a hairline tear.
Nothing.
He reassembled the pump, bolted it back on, and connected every line exactly as the diagram dictated: Tank vacuum to the top-left port. Manifold pulse to the top-right. Fuel out the bottom to the carb. suzuki quadrunner 250 fuel pump diagram
Put-put-put.