XP 800 1996 on off throttle

[JustinCorbett]

Just wondering can anyone help. I've just purchased my XP 800 and this is a continuous problem. Plugs are NGK BR8ES / compression is 150psi on each cylinder and my regulator is working as it should. All fuses are checked and all electrics. I've took 10mm off the ignition leads and refitted.
When the ski does this and it's brought to the shore the back cylinder plug is wet. Plugs changed around again it goes flat out to 40mph and keeps giving you the power on and off for 2 seconds. It wets the back cylinder again. Engine feels nice and cool to the touch ( around 60 oC ) .
It seems to loose power after 30 minutes in the water and that is the time I bring it in again.
The ski has always been in fresh water all its life and it starts and runs smoothly on both cylinders.
Out of the water it will run and rev clean and sharp to the limiter instantly. Back in the water on the pull to 40mph it's a rocket and then does the same thing again.

Any help would be much appreciated

 

[Pwnage1337]

Sounds like a fueling issue. What condition are the carbs in?

 

[JustinCorbett]

I've been avoiding the carbs hoping it might be electrical. The fact the rear plug kept getting wet made me wonder.
Them carbs look like alot of work to get off let alone rebuild.
I can't understand why inline fuel filters weren't used from the factory. Why bury them inside the carbs

 

[Pwnage1337]

There is an inline filter. It is the water separator.

The only thing that could cause your plug to be wet is either the cylinder isn't firing and the plug is getting soaked with gas, or the carb is metering wrong, or the engine is ingesting water in the rear cylinder.

Do you have stock air box?

 

[JustinCorbett]

I have a stock air box yes. Everything about the ski is standard. The grey fuel lines as well

 

[Pwnage1337]

That's bad news!! I would stop running the ski before you blow it up.

Rebuild the carbs and replace fuel lines. I'd change the fuel selector and water separator too.

 

[POPPS]

You also might want to check the condition of ignition wire leads from the coil in the rear electrical box,,,water can get trapped in there and corrode the connection.

 

[JustinCorbett]

Hi all. I have opened up the fuel selector and it is clean. I took off the water separater and cleaned it. It wasn't really that dirty.
When I opened the tank and blew some air threw the vent at the top I noticed a vent on the side of the ski. Why would it be their and why would it be under water as well ?? That seems very strange to put a vent here when water could be drawn in when the tank is emptying as the ski is in use?
What's your views on this?

 

[mikidymac]

You really can't clean the fuel selectors as they will leak air once you try to take them apart and the rubber parts inside go bad. Just replace it with a new one.

The vent on the rub rail is actually a pressure relief not a vent into the tank, the vent into the tank is under the round rubber bumper for your hood to close on.