2006 gtx sc

[Osubauer]

I'm looking at buying a 2006 GTX SC with 134 hours. The ad says "freshly serviced" but I don't know if the supercharger has been rebuilt. In my search for a Sea Doo I have generally ruled out the supercharged ones because I feared the extra maintenance, cost, etc. Im looking for a good 3 up model that my wife can ride and is capable of pulling a tube. It doesn't have to be set your hair on fire fast but fun no less. Any advice on what might be the best for my needs?

 

[lamajama]

If the current owner has no proof the SC has been serviced, then you'll have to reduce your offer as you'll have to do it yourself for sure.

With the SC models, you have to budget the approx $400 every 2 years or 100 hours for sure. That being said, any of the 4tec 3 seater's will pull a tube with no issues
and are really comfortable, SC or naturally aspirated.

 

[Coastiejoe]

I'll second that.. If it can not be proven, you must assume it needs rebuilt. This is not nearly as critical when the SC has metal washers, but the 06 had factory ceramic washers. If they fail, you will be pulling the engine to remove the broken bits at a minimum.

Also, the 2004 to mid-2006 4-tec engines had sodium filled valves. Compared to the solid core, they are prone to fail. If they fail, SERIOUS damage is the result and can easily cost 4 grand to fix.

The sodium valves are stamped 72 on the stem and the solid are stamped 75. You can see this stamping by removing the valve cover. In my opinion, is they are sodium filled you need to discount the asking price. As if it were me buying the ski, I would replace the valves upon purchasing it.

Here is a pic of the stamped numbers.

 

[Spimothy Leary]

one more thing, the last 3 4tec's i've come across from 06-08 have had at least one bad rear motor mount, check those out and make sure you have no issues there.

I forget which year the flywheel bolts no longer became a concern.

 

[Osubauer]

Found out its not supercharged. It has been dealer serviced every year and the seller states it has about 15 hours over the past 3 years.

Question: how hard is it to change the valves and what is a ballpark price to do that?

 

[Coastiejoe]

The head has to come off to do the job,,

 

[Osubauer]

Just watched a youtube video on the job. All I can say is WOW! That's a big job. Is the valve failure a common problem? What is the cause of the failure?

 

[Coastiejoe]

Just watched a youtube video on the job. All I can say is WOW! That's a big job. Is the valve failure a common problem? What is the cause of the failure?

The original valves are sodium filled and are not as strong as the solid core. They tend to fail where they slide through the head.

Some never change them and never have a problem. Others fail for no clear reason.

 

[Sea Dood]

This isn't the reason they break. I did some analysis and wrote up a big sticky on Greenhulk on this topic. These valves always fail at the weld joint. For those that don't know, these valves are made by a friction welding process, where they use an alloy of one material for the valve head, and a different alloy for the stem. It is cheaper to do this than making them from a large bar.

The alloys they use to make them from corrodes very easily, and even more so once heated to a high temp. If you look at the weld joint area of the exhaust valves in an engine with broken valve(s), you will see lots of corrosion pitting right at the weld joint area. These engines always have 100% humidity in the exhaust chamber, and you will notice that most (not all) of the failures are on valves in the rear-most cylinder, which runs the valves the hottest, and is closer to the waterbox.

On these alloys, corrosion pitting leads to tunneling/microcracking, which eventually grows into a full crack, and off pops the head of the valve, right at the weld joint. This is because the weld joint is more vunerable to embrittlement, so microcracking can spread easier into a full-blown crack.

The later valves are made from Inconel, which is both corrosion-resistant, and tougher. It tends to bend rather than break.

The consensus is if you always fog (correctly fog) before any extended storage, you lessen the possibility of this happening.

Also, most of the failures are on the higher HP (SC) engines, which runs the valves hotter.

 

[Coastiejoe]

This isn't the reason they break. I did some analysis and wrote up a big sticky on Greenhulk on this topic. These valves always fail at the weld joint. For those that don't know, these valves are made by a friction welding process, where they use an alloy of one material for the valve head, and a different alloy for the stem. It is cheaper to do this than making them from a large bar.

The alloys they use to make them from corrodes very easily, and even more so once heated to a high temp. If you look at the weld joint area of the exhaust valves in an engine with broken valve(s), you will see lots of corrosion pitting right at the weld joint area. These engines always have 100% humidity in the exhaust chamber, and you will notice that most (not all) of the failures are on valves in the rear-most cylinder, which runs the valves the hottest, and is closer to the waterbox.

On these alloys, corrosion pitting leads to tunneling/microcracking, which eventually grows into a full crack, and off pops the head of the valve, right at the weld joint. This is because the weld joint is more vunerable to embrittlement, so microcracking can spread easier into a full-blown crack.

The later valves are made from Inconel, which is both corrosion-resistant, and tougher. It tends to bend rather than break.

The consensus is if you always fog (correctly fog) before any extended storage, you lessen the possibility of this happening.

Also, most of the failures are on the higher HP (SC) engines, which runs the valves hotter.

I wasn't implying it was the sodium that caused the failure. Just that this style of valve is a weaker design as compared to one piece solid core valves.

 

[Sea Dood]

Understood. I just wanted to point out that it isn't just because the stem is hollow, it is other factors that cause the failure.

There have been cases of the new solid valves failing at the same spot. The weld joint is where all of them, old and new, fail.

 

[Spimothy Leary]

bottom line, they must be replaced if you plan on holding onto the ski for any length of time. Valve Failure is expensive !