RXP-X hits top speed at a slow pace

[rockonup]

So I have two 2008 RXP-Xs. The one Ski hits top speed like it should in matter of seconds we will call this one the yellow ski due to the MC numbers (It's how I tell them apart). The other ski we will call the green ski. The green ski hits top speed but very slowly compared to the yellow ski, and also made a more rougher idle noise. But it does eventually hit top speed. So I went to my local dealer. We ruled out its not the super charger because it hits top speed and it is not cavitating so I know its not the prop or wear ring. He said to change the plugs if I haven't in awhile. Which I haven't and didn't realize it. So just a bit ago I changed out all 6 plugs (3 in each) I notice on the green ski the one having speed and take off issues that the plugs were rusty looking and dry. The yellow ski had the rusty burnt look but had a little bit of fuel or oil on them. See the picture bellow, the yellow one on the left and green on the right. I haven't lake tested it yet because of weather and time, but wanted to see what everyone else seems to think it could be before doing so. I fired both up and that noise has gone away on the green ski and yellow one still running strong. They seem to sound and look fine as I can tell. The RPMS hit the 7 and 8 no problem. Any thoughts or suggestions to help me sleep will be great. Thanks Again.

[Speedjunky64]

Might want to take a look at your inter-cooler.
I had similar looking plugs and the reason it looked dry and rusted was because the I/C had gone bad and was spraying water in the engine.

[Lightning1]

I agree with the intercooler. I would pressure test it to make sure it is good. Mine leaked and caused a rough idle, but it would reach top speed.

[rockonup]

Might want to take a look at your inter-cooler.
I had similar looking plugs and the reason it looked dry and rusted was because the I/C had gone bad and was spraying water in the engine.

So I went to the dealer to show him and I had check the oil sticks the Green one had a small tint of milky oil, which what your saying could be true as well. The dealer said to idle around with the seat off to see if anything is spraying or leaking in. Then get the engine hot by running it for awhile to get rid of that little bit of moister, if it was serious my oil pressure switches would be throwing an error code. This is the first I had them out this year and we assume could be from winter and after the winterization. So should I try what the dealer said or will it be it to take apart the intercooler to take a peak at it. And what will I notice if it did go bad? Thanks again for responding!

[rockonup]

Also the rough idle went away after new plugs just to update you on that.

[Speedjunky64]

Well, safest way to test it would be on the trailer with garden hose attached to ski.
Unhook your I/C hose going to throttle body and give it a couple quick blip with the feeder and see if there's any water coming out. If so, and I believe so, replace I/C and oil/filter.

[Speedjunky64]

Pressure testing it would be the best test if it's leaking very little.

[rockonup]

Well, safest way to test it would be on the trailer with garden hose attached to ski.
Unhook your I/C hose going to throttle body and give it a couple quick blip with the feeder and see if there's any water coming out. If so, and I believe so, replace I/C and oil/filter.

Thank You very much, I was also going to seal up the inter cooler and drop it in a tank of water with air hose hooked to it to see any leaks. But thank you for the advice I'm going to try it tomorrow night.

[rockonup]

Pressure testing it would be the best test if it's leaking very little.

By chance do you know how much pressure these can handle?

[Speedjunky64]

There's been many treads about this, here's one: http://www.greenhulk.net/forums/showthread.php?t=183486