Tohatsu Fuel System Diagnosis: 60 Second Checklist for Fuel Issues
Most Tohatsu running issues are fuel delivery, air leaks, or a blocked vent. Use this 60 second checklist to spot the cause fast before you start replacing parts.
Fuel issues on a Tohatsu outboard usually come down to one thing: the engine is not getting a steady, air free supply of clean fuel. Before you dig deeper, run this 60 second checklist.
Diagnose in 60 seconds
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Tank vent open? If your portable tank has a vent screw, open it. A closed vent causes vacuum and fuel starvation.
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Fuel level and fuel quality: Confirm there is enough fuel and it is fresh. Old petrol can cause hard starting and stalling.
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Primer bulb: Squeeze until firm. If it never firms up, you likely have an air leak, loose clamp, cracked hose, or a faulty bulb. Make sure the bulb arrow points towards the engine.
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Quick connectors: Disconnect and reconnect firmly at both ends. A half seated connector can restrict flow or let air in.
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Fuel line condition: Look for kinks, soft spots, splits, or collapsing hose, especially near the ends.
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Filter check: If you have an in line filter or water separator, inspect for water, debris, or a blocked element.
What the symptoms usually mean
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Starts then dies: vent closed, clogged filter, weak primer bulb, air leak at connectors.
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Surges at speed, loses power: restriction in line or filter, tank pickup issue, debris in carb or injector supply.
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Only runs with choke or extra prime: likely lean, usually an air leak or blockage.
Carry a spare bulb, hose clamps, and an in line filter, and replace fuel lines that show cracking or stiffness.
