frustrated as hell last weekend on my 24′ center console with the yamaha f150. out past the no-wake zone in 2-3ft chop, suddenly the engine bogs down, loses rpm, and starts surging like it’s starved for fuel. thought it was classic fuel starvation-checked the tank pickup (full, no debris), squeezed the primer bulb (firm), even ran the aux tank to rule out main tank vent clog. nada.
hit up the marina on vhf, guy says “swap the fuel filter, probably ethanol crap gumming it up.” pulled the low-pressure filter inline, crystal clear. online forums screaming “bad ecm or ignition coil”-no codes on the diagnostic port, and coils tested fine with a spark tester.
towed back to the slip, next morning i notice the goddamn vapor separator tank (vst) hose kinked 90 degrees from where the cowling latches pinched it during trailering. uncompressed it, bled the system, fires right up smooth as silk. lost a full day of fishing over a ¾″ rubber hose fold.
tip for you guys: always double-check vst lines and all fuel routing under cowling after any haul-out. those yamaha 4-strokes are finicky about uninterrupted pressure-under the hood, it’s 36-44 psi at idle to the injectors, drops even 5psi from a pinch and you’re surging. saves calling a tow.