If you don't do any other due diligence buying a used jetski, just do this 1 thing.

This is it: View the actual service history with your own eyes. Either the PDF copies or hard copies.

Make a real effort to view the service history. A surprising amount of purchasing mistakes could have been avoided by this one task.

The most common false statements from sellers are:

• "It's been serviced regularly". Which they think is every 2 or 3 years (see notes below).

• "It's not due for service". 9 times out of 10 this statement is incorrect (see notes below).

When buying a used jetski, you want either:

• To confirm a very recent service has been done (within a month is ideal).

  OR,

• A pre-purchase inspection.

We recommend getting the service done if it hasn't been done very recently, over getting the pre-purchase inspection. Because the full service includes very similar checks to the pre-purchase, this will save you the cost of the pre-purchase and having to get a service in the near future ($475 - $900).

You can bargain with the seller to get the service completed if they know you are serious and it will seal the deal. Or, offer to split the costs with the seller depending on the initial price and current negotiations.

Looking at the service history a seller presents to you:

The easiest guide for service intervals for Yamaha and Seadoo in NZ is:

1st service: 12 months from purchase/first use, OR < 25 hrs - whichever comes FIRST.

2nd and subsequent services: 12 months from date of last service, OR 50 hours from last service - whichever comes FIRST.

Check the service history dates to make sure all invoices are present. If there are any gaps in years, it may pay to double check with the seller. Get their authority to ask their service agent a few questions about the ski, and then you can ask the agent if any invoices are missing from the documents you have been given.

Look for any additional notes on the service invoice about condition, parts coming up due for replacement next season, any diagnostic faults, and additional parts other than spark plugs and oil filter.

Any of the following issues should ring alarm bells which will require further investigation until you understand what future issues it may cause:

• Any electronic or wiring issues

• Any starting issues mentioned without explanation

• Any faults or codes mentioned

• Any future work due - find out costs

• Any mention of roll over, water in the oil

• Any seized parts - find out relevance and costs

If the sellers says "It's been regularly serviced" but has only 2 invoices for a 5 year old ski, that is quite common. But refer back to the recent service or pre-purchase rule for safety.

If the seller says "It's not due for service" this is often not a deliberate lie, as they may believe the service intervals are longer. Whatever their belief is and how they came to that conclusion, understand that the above service intervals are your best protection to avoid common problems. We have been proven correct many times in the last 20 years on service intervals, and jetski's are only becoming more fragile not stronger.

Rusted oil filters are commonly found on Yamaha's which haven't been regularly serviced. A tiny pin-hole in the casing can cause major oil loss when at operating temperature and result in engine damage if riding continues.

For an in-depth guide for first-time jetski buyers, read this;