rought idle and low rpm surge on 2003 seadoo sportster 4 tec nonSC

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Drdjewel

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New to this forum. Seems incredibly helpful. Alot of very knowledgeable folks out there. New owner of a used sportster. 2003 4tec nonSC. Live in Florida, salt water. Had a mechanic inspect. good compression all cylinders, no visible engine problems. Ran fine on hose, though loud. First run yellow check engine light and limp mode after 5 minutes. Would resolve if shut down and restart only to happen again after another 5 min. Didn't help that in my first 30 seconds of use I sucked up a 1 in rock that made the whole thing sound like a garbage disposal until I got back to the ramp and got it on land. Removed with needlenose pliers under the boat, at the impeller. But I did run it that way for a few minutes until I got back to the ramp. Took to dealer to get fault code read. Replaced oil pressure switch, as per computer readout. That was the only fault code in there when I took it to the dealer to get it read (though that fault occurred 134 times, according to the computer). They also recommended replacing the "shut off solenoid and gasket" which I ordered but did not replace yet, as it takes a week to get the part. Also replaced all 3plugs with NGK. Back to water for test. No more check engine light. Now very fast, good power. Ran for an hour with no light. BUT - very rough idle, with RPM surge. If at complete idle seems OK, but tap it up a little and it runs rough, with erratic surges, until I get past a certain RPM then it runs strong and fine. Tach and fuel gauges are out, so cannot elaborate on RPM (could this be a fuse since both gauges are out? Engine/oil/temp gauge obviously working...I'll save that for another post). So this was a long-winded way to my question:

What could be causing the rough idle (really just above idle)? Could it be this shut off solenoid which the dealer recommended (which is, BTW, a $200 part). The original one does click when I turn the boat on. I even took it off to inspect and lube, seems to go in and out fine, though maybe a bit sluggish. Don't know how long the gas has been in there, though does not smell bad, and boat does run strong at higher rpm. Added Stabil and enzyme cleaner. Any recommendations as to where to start?

Also, this boat sounds like a garbage disposal when out of the water. I have read lots of prior posts that say the "bag of rocks" sound is normal, but this is LOUD. Seems to me bearings are shot. Is this hard to replace? Am I causing damage by running this way? Seems fine in water, with no slippage, no unusual sounds.

Thank you in advance for your help. This seems like a very helpful community. Hoping to get this thing running reliably. My kids are itching to go wakeboarding...
 
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