2012 STX-15F Rear Air Ducts

[Muzza WA]

Hi all, at the rear of my JetSki, under the grab-on handle on the hull, are two plastic corrugated black pipes (left and right) that attach to the holes in the top of the hull under the seat, and hang down fairly deep into the hull. On the microfiche they are identified as Air Ducts. Neither the Service Manual nor the Owners Manual give them any importance, the question I have is what is the down side of removing them, other than maybe directing water to the bottom of the hull, towards the rear of the hull, that might get in under the seat?

The reason I want to remove them is simply to get more space as I am installing a second battery, they take up a load of space and are fairly robust and difficult to work with.

thanks for your comments, observations and advice.

[steve45]

No problem with removing them--until you flip it upside down!

Then it will instantly flood your 'Ski and possibly sink it.

[Muzza WA]

I thought about that, however, the huge opening in the hull under the forward seat would in any case allow a huge amount more water to enter the hull, than the smaller opening under the rear seat surely?

[steve45]

There should be a seal around the perimeter of both seat cushions.

[Muzza WA]

There should be a seal around the perimeter of both seat cushions.

Hi Steve, yes there is a seal around both openings, however there is no seal where the duct openings exit the hull underneath the seat. I am also not convinced that the seals would actually stop much water getting in, there is insufficient pressure on the seat fittings to create a water tight seal, in my opinion. So where does that leave me? Water can enter the hull through 4 openings in the top of the hull....under the front seat, under the rear seat and from both of the duct entry points......again, I am confused how the duct pipes help in this regard. Thank you.

[711jrp]

Flip it and see, make sure someone is filming.....

[Muzza WA]

Great informative well thought out response, thanks for the help!

[steve45]

The hoses buy you time. Time to swim back to the 'Ski and flip it back upright. The 'Ski is not supposed to sink completely, but I've seen them get to the point that only the handlebars or front bumper are above water. The seat cushion provides some flotation until it becomes water logged. The fuel tank will provide flotation if the fuel level is moderately low. My 2010 Ultra LX has two pieces of styrofoam flotation in the rear of the hull, my 2013s only have one piece. When I contacted the Kawasaki engineering department to find out what the deal was and try to get a replacement foam insert, they told me that their testing showed that it would 'float' with only one piece of foam--so they saved a couple of dollars by removing the second piece. They would not provide the second piece of foam. They wouldn't even sell it to me, nor provide a part number.

[pro1200]

Those air ducts split in two on my '15 15F and I'm too cheap to buy replacements. I know the risk of not having them (massive intrusion of water into the hull when it's inverted) but I choose to accept that risk. Your feelings are what should guide you.

[TMiller]

There is also a large opening in front of the steering under the cowl. I have an extra hull or 2 if I was really bored I would like take it and put it in the water upside down. If everything on the bottom of the hull was "tight" pretty sure it would float even with no seat or trim, should stay airlocked on glassy water of course. Only if someone tried to upright or if the water was really choppy would the water pour in.

I think it is a better idea to leave them in if possible