05 Sportster SCIC fouling plugs

[Giligan]

Well, we thought we had this issued, licked, but it insists on constantly rearing it's head. Here's the deal:

2005 Sporster SCIC 215.
Runs great on new plugs for the first hour or so. After a few starts and stops, boat starts running very ragged. When we pull the plugs they are so covered in soot, that you can't see any porcelin.

We've eliminated fuel, as we've run several tanks through. Had the boat into a Sea Doo dealer at the end of the summer. They said there were no fault codes

I'm so frusterated at this point that I wish we never bought this boat. It doesn't have very many hours on it, and everytime we go to use it, we wind up dissappointed.

Does anyone have any advise to steer me in a different direction? Should I check the charging system, does anyone think this could be a voltage problem? I'm at a complete loss right now. Any help would be truely appreciated.

 

[Giligan]

Does anyone think this could be a voltage problem? I'm kind of leaning that way right now. I have the battery out of the boat and on the charger. It may be shot, but has already replaced once throughout this ordeal (which has been going on for 1 1/2 seasons). It has been charging for about 24 hours at 2 amp, and is only at 85%

I plan on checking it with a multimeter once I get it charged (or get a new battery) and back in the boat to see if it possibly is a bad rectifier. Do the symptoms sound like they could be indicative of that type of problem?

Any ideas would really be helpful.

 

[normmb]

I feel you're pain

I have the same boat:

just a shot in the dark,
1. check the engine ground ( last year i did not connect all of the ground wire to the battery and ended up with erratic idle and "check engine" light

2. too much oil?

is it happening on all cylinders?

 

[Dennis]

There's a possibility that the intercooler in the intake plenum has a hole in it causing the engine to injest water. Has the boat been used in salt water?
I'd bypass the intercooler, install new plugs and see how it goes.
There's also the possibilty that the supercharger has a bad seal and pushing oil into the intake plenum. Take the hose off at the throttle body and see if it is real oily inside.

DAWG

 

[Giligan]

Thanks for the ideas, I will look into those. I am having the problem in all 3 cylinders. If I put in new plugs, the boat runs again for an hour or so until the problem repeats itself. I will make sure I have a good ground on the battery when I reinstall. I'm going to check the voltage for S & G's as well to make sure it isn't a regulator/rectifier problem.

Hoping to make it back out to the lake in the next 4 or 5 days. In the meantime, keep the ideas coming. . . I'm willing to try anything at this point. Just want to enjoy this moneypit at somepoint:ack:

Edited to add: The boat has never been in salt water

 

[Dennis]

Intercooler problems are usually because of salt water corrosion.

DAWG

 

[Giligan]

Okay, thanks Dennis. I will check on the Supercharger seal though.

 

[Dennis]

I"m assuming you're using the correct spark plugs. NGK DCPR8E
Nothing else will do.

DAWG

 

[Giligan]

Yep, never used anything but. Always gapped to .030". Also have never used anything but premium fuel

 

[Dennis]

Black, sooty spark plugs indicates the engine is running too rich. You either have not enough air or you have too much fuel. I would start by making sure there are no air intake restrictions. Don't assume anything. Take the front air box apart and make sure nothing is inside (rag, small dog etc.) Check the air tube leading from air box to the supercharger for debris. If OK then we have to assume that engine is getting too much fuel.
Basically, there are three sensors that control fuel. Air temp, coolant temp and manifold pressure. You need to test the air and coolant temp sensors with a ohm meter(cold engine).
Air temp sensor is at the front of the air intake plenum pointing to the front of the boat. It should read between 2280 and 2740 ohms at 68 deg F.
Coolant temp sensor is at the rear of the cylinder head, up high on the rt hand side. It should read the same as air temp sensor.
The manifold pressure sensor is located on intake plenum, towards the front, pointing to the rt side of the boat. You won't be able to test this sensor but you do need to remove it and check for debris (oil, carbon, etc). Remove the retaining bolt or screw and gently pull the sensor out of the plenum and inspect it. This sensor can test good at the dealer but be bad, therefore, if the other sensors test good then I would replace this sensor and hope for the best. Make sure the harness connections at these sensors are clean. Good Luck, DAWG

 

[Giligan]

Last but not Least. . . feel free to scold me if this is a stupid question. Because this boat is SCIC (intercooled) Do I need to have the boat on the water to safely test all these things? The last thing I want to do create more problems than I already have.

On testing the sensors, does the boat need to be running? I know I need to do it with the boat cold, just want to make sure that I am getting proper info.

Thank you so much for all your time and suggestions. I am going to get to work tomorrow morning and hopefully tackle this thing once and for all.

 

[florastuart2001]

I have the same boat, I only have a problem with plugs when I let it idle too long, then have to run it at speed to get it to clear out. Don't let boat idle, cut engine instead. Hope this helps.