If your outboard idles in the slip and then falls on its face at high throttle, the problem is usually fuel delivery under load — not a weak engine and not the propeller.

Before you buy parts:

1. Confirm the symptom. Idle and mid-range are fine. Power only drops at high throttle or under load. Dock checks lie.

1. Tank vent. A vacuumed tank starves the engine once demand spikes. On a controlled test run, with a spotter, crack the fill cap. If power comes back, the vent is clogged.

1. Primer bulb. It should stay firm after you squeeze it. If it slowly goes soft, you are pulling air or the check valve is done.

1. Filters and anti-siphon. A restriction that hides at idle will show at WOT. Check the in-line filter, tank pickup, and anti-siphon valve before you touch the powerhead.

1. Hoses and fittings. Cracked, collapsed, or heat-softened hose can pinch the moment the engine asks for fuel.

Write down what you tested. The goal is one failed check, then a fix — not a parts catalog.

That sequence is the map. Use it before you spend a dollar on a propeller or a rebuild.