How do I fix outboard choke or enrichment problems?
Choke / enrichment problems · Symptom: Cold engine won't start, or floods.
Quick answer: Most often: cold start without choke/prime, choke left on after warm-up (flooding, soot), using choke on an already-warm engine. Start here: Follow your manual's cold-start sequence. Tohatsu small 4-strokes, for example: choke fully out, throttle to START, pull; push choke back once running; choke not needed when warm. If that doesn't fix it, work through the checks below, and see a marine mechanic if you're unsure.
Likely causes (most to least common)
- Cold start without choke/prime
- Choke left on after warm-up (flooding, soot)
- Using choke on an already-warm engine
- Stuck choke plate, linkage, or (electric) choke solenoid
Safe owner checks & fixes
- Follow your manual's cold-start sequence. Tohatsu small 4-strokes, for example: choke fully out, throttle to START, pull; push choke back once running; choke not needed when warm.
- Tohatsu: if no start after 4–5 attempts with choke, push choke back in and retry (avoids flooding).
- Unstable idle when cold: partial choke briefly, per manual.
- Electric choke (some Tohatsu EP/EPT): if solenoid fails the manual describes closing the plate by hand — follow it exactly.
- Check choke linkage moves freely (listed in Tohatsu inspection chart).
Parts / tools
Usually none; choke linkage parts if worn.
Call a marine mechanic when
Choke linkage seized or broken; electric choke solenoid failed; still won't start cold after correct procedure (carb service). If you're on the water and unsafe, call TowBoatUS/Sea Tow or the Coast Guard (VHF 16).
Sources
- https://www.tohatsu.com/marine/common/owners_manual/MFS456D_US_EN_web.pdf
- https://www.tohatsu.us/docs/pdf/manuals/Toh_MFS15C_20C_v2.pdf
- https://defender.com/assets/pdf/yamaha/f15-f20-2022-owner-s-manual.pdf
Values not stated here are model-specific; check your owner's manual.