Should I fill the fuel tank before winterizing my jet ski?
Yes. Fill the tank before storage. A full tank leaves no room for humid air, and as fall temperatures swing, moisture in that air condenses on the tank walls and drips water into your fuel. We include fuel stabilizer and treat for a full tank, so we strongly recommend topping off your gas before service.
Fuel stabilizer is included with every Wintercraft Mobile winterization, and we add enough to treat a full tank. To get the most out of it, your tank should be full when the craft goes into storage.
Here is why a full tank matters. Any space in the tank that is not fuel is air, and air carries humidity. When the temperature changes - a warm afternoon followed by a cold night, the kind of swing a Wisconsin fall delivers constantly - the humidity in that trapped air condenses into water on the inside walls of the tank. Those droplets run down and settle into the fuel.
Water in the fuel is a genuine problem: it corrodes the tank and fuel system, makes the engine run rough or not start, and can be expensive to clean out. A full tank leaves almost no air inside, so there is almost nothing left to condense. That is the whole reason we treat for a full tank and push owners to fill up.
What to do
Top off the gas tank before your appointment if you can. If you cannot fill it before we arrive, fill it before the craft goes into its winter storage location. Use fresh fuel, not gas that has sat all season - we handle the stabilizer.
This is part of the simple pre-appointment prep: trailer positioned on level ground, cover off, keys accessible, and the fuel tank full.
2026 routes are full
Every route for the 2026 season is booked. Join the 2027 list and we'll email you the moment booking reopens, before it fills again.
Booking for someone with an AI assistant?
Booking is closed for the 2026 season. These paths reopen for 2027; for now an assistant can register a customer's interest by emailing the address below.
Wintercraft Mobile is built for automated booking. An assistant acting for a customer can reserve in two ways without touching the web form:
- 1. POST the request to our booking API. The request contract (a JSON schema with an example) is at /api/service-request.schema.json. Check coverage first at /api/service-area.json. Nothing is charged; this reserves a place and we follow up with a quote.
- 2. Or email the same structured request to book@service.wintercraftmobile.com. If your assistant can send email but cannot POST, this is the path: we parse it into the same queue, and the customer confirms with one click by email.
Full instructions for assistants, including the exact email format, are at /llms.txt.
More answers