Boat Guru
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Marine mechanic AI · for owners who do their own work

Diagnose your boat in 2 minutes, not 2 weeks.

Boat Guru is an AI marine mechanic that helps you troubleshoot engine, electrical, fuel, and drive-system problems on outboards, sterndrives, jet drives, and small marine diesels — vintage 2-strokes through brand-new EFI. All major brands. Available the moment something goes wrong, not 4 weeks from now.

Start free — one complete diagnosticSee pricing →

Covers Mercury, Yamaha, Suzuki, Honda, Evinrude, Johnson and more.

2018 Mercury 90 EFI, won't start. Cranks fine, fuel pump primes, but no fire. Spark looks weak on cylinder 2. What do I check?

Most likely: failing CDI/ignition coil pack on cylinder 2. Mercury 90 EFIs of that era have a known weak-spark failure mode on individual coils.

Diagnostic order:

  1. Swap the cyl 2 coil with cyl 1 — if the weak spark moves with the coil, you've confirmed it.
  2. Check the trigger / stator output (should be ~5–7 V AC at cranking).
  3. Confirm 12V to the ignition pack with key on.

Coil part: Mercury 339-879984T00 (or Sierra 18-5187 aftermarket).

31,000
unfilled marine technician jobs in U.S. dealerships
$80–$150/hr
average shop labor rate
2–4 weeks
wait at most marinas in season

A single dealer service call typically costs $250+. One avoided visit pays for the year.

Built for the engine in your driveway

Diagnose anything that runs

Outboards (2-stroke and 4-stroke, carbureted to EFI), sterndrives, inboards, jet drives, small marine diesels — major brands above. Older and discontinued engines too.

Photo diagnosis

Snap your engine, a corroded connector, a fuel leak, a cracked impeller. The AI looks and tells you what it's seeing. Plus & Pro

Saved boat profile

Tell us your hull, engine, year, HP, mods. Every answer is grounded in your boat — not generic advice. Plus & Pro

Step-by-step procedures

“Won't start” → compression, spark, fuel/air. Sized for a backyard mechanic with hand tools. Includes torque specs and warns you off the parts that need a pro.

Why not just use ChatGPT?

ChatGPT is great for a lot of things. Boat repair isn't one of its strengths.

ChatGPT
Boat Guru
Knows your specific engine
Asks every time
Saved profile
Photo diagnosis
Generic
Marine-specific
Vintage / discontinued engines
Patchy
Deep coverage
Parts lookup with cross-references
—
Coming soon
Safety guardrails for fuel / electrical / steering
—
Built in
Cost
$20/mo
$25/mo or $199/yr

How it works

  1. 1

    Sign up free

    One complete diagnostic, no credit card. Bring your worst current problem.

  2. 2

    Get a real diagnosis

    Not a list of 12 possibilities — the most likely cause first, ranked alternatives, and the next test to run.

  3. 3

    Upgrade when it pays for itself

    Plus is $199/yr — less than one shop visit. Pause off-season. Cancel anytime.

One marina visit pays for the year

Free
$0

One complete diagnostic to get started

Plus
$199/yr

Ongoing diagnostics, photo diagnosis, 1 active boat

Pro
$399/yr

Multiple personal boats and mechanic handoff reports

See full pricing →

Common questions

Is this safe? What if it's wrong?+
We tell you up front: AI answers can be wrong, and any safety-critical work — fuel lines, electrical, steering, anything that could leave you stranded or in flames — needs a certified mechanic to verify before you wrench on it. We won't help you bypass kill switches or skip torque specs. See the full disclaimer.
What does it cover that other AI tools don't?+
Vintage 2-strokes, older OMC sterndrives, jet drives, pontoons, small sailboat auxiliaries, bass-boat-specific systems. Most marine AI tools only cover modern Mercury, Yamaha, Suzuki, and Honda outboards.
Can I cancel?+
Yes, anytime, from your account. Subscriptions stop at the end of the period — no prorated refunds, but no surprise charges either. You can also pause for the off-season.
Do you train your AI on my chats?+
No. Your messages are sent to Anthropic's Claude to generate a response. Anthropic does not train its models on API submissions. We don't sell your data and we don't use it to train third-party models.
What if my boat is something weird?+
Try one complete diagnostic on your specific engine. If we can't help, you've spent nothing.

Stop driving from shop to shop. Start with the diagnosis.

Start free →See pricing

One complete diagnostic, no credit card.

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