My Jet Ski Won't Start: 4 First Steps to Diagnose the Problem

It’s a perfect day in Ocean City. The water is flat, the sun is out... and your jet ski won't start. There's nothing more frustrating. You get the dreaded "click" or, even worse, just silence.

While some issues require a full diagnostic at the shop, there are often a few simple things that can cause a no-start. Before you assume the worst, run through this 4-step checklist. This is the exact "baseline" we start with to help diagnose the issue.

Watch Our Quick Guide on TikTok!

We made a short video walking you through these exact steps. Sometimes it's easier to see it done!

1. Check Your Battery (The #1 Culprit)

This is the most common reason for a no-start, especially at the beginning of the season.

• Is it charged? A battery can (and will) lose its charge just from sitting. Even if it's new, it may have drained. Put it on a charger.

• Are the terminals tight? Go to your battery and physically wiggle the red (+) and black (-) cable connections. If you can move them by hand, they are too loose. A loose connection can't deliver the power needed to start the engine, even if the battery is fully charged.

• Are they clean? Look for white or blue-green crust (corrosion) on the terminals. This can also prevent a good connection.

2. Check Your Lanyard / Key

It sounds simple, but it happens to everyone. Your jet ski is designed not to start unless the lanyard is properly attached.

• Is it fully seated? Make sure the safety lanyard (the "key") is snapped firmly onto the post.

• Is it the right key? If you have multiple skis, make sure you're using the correct programmed key for that specific watercraft.

• Is the post clean? On some models (especially older Sea-Doos), the post and the cap on the key need to be clean to make a good connection.

3. Check Your Fuel Level

Another simple one that's easy to overlook.

• Is there gas in the tank? Don't just trust the gauge, especially on an older ski. Gauges can fail. Open the cap and look inside.

• Is it fresh? If your jet ski has been sitting all winter with untreated fuel, the gas may have gone bad. Old fuel can clog the system and won't ignite properly.

4. Check Your Oil (Especially for a "Milky" Look)

This is a critical safety check. Your jet ski's computer may prevent a start if the oil level is dangerously low, but more importantly, you're checking for engine-killing water intrusion.

• Check the level: Pull the dipstick, wipe it clean, re-insert it fully, and pull it out again. Is the oil level between the "Add" and "Full" marks?

• Check the condition: Look at the oil on the dipstick. It should look like normal, dark-to-light-brown oil.

• THE RED FLAG: If the oil looks milky, "like a chocolate milkshake," or creamy, STOP. Do not try to start the engine. This means water has gotten into your engine, and trying to run it can cause catastrophic damage.

Still Won't Start? It's Time for a Pro.

If you've checked these four things and your jet ski still won't turn over, you've done your due diligence. It's likely a more complex issue, like a bad starter, a clogged fuel pump, or a sensor failure.

Don't spend your valuable time on the water guessing. Bring it to us, and we'll run a full diagnostic to get you back on the water safely.

Call us at (410) 973-2890 or click below to schedule a service drop-off.