2004 Sportster LE runs rich at idle or slow speeds

[xexman44]

Hi all,
New jet boat guy here. Just bought a 2004 Sportster LE. Excellent shape, I think. Have lots of big boat experience and a lifetime of two stroke experience. Just wondering what the thoughts are on the rough idle deal. Brand new high test gas. Owner said the oil is Ski doo synthetic. Two brand new plugs.
Starts right up. Get a few warning beeps for about a minute then go away. All long as you stay above half throttle or more it runs great. Smooth, no oil in the exhaust. When you slow down to come back to the dock, it immediately starts to load up, run rough and you can see the smoke in the exhaust. Just wondering if there is anything I should know about these engines or the injection system before I plug into the computer and start screwing things up? Any and all comments are appreciated. This boat is the most fun I've had on the water in a long time! I think this is going to be fun.
Thanks for the help.
Joe

 

[OhNoItsMe]

Not sure this will be much help but after my engine was rebuilt the timing on my oil pump was modified to about 30:1 instead of 50:1 and I had the same issue at low rpm's lots of smoke and idle was kinda rough but after breaking in the engine the timing was put back at 50:1 and now it's all good.

I had that done by a dealer as I just got the boat and was in hurry to get it up n running so I'm not sure how you can check/modify the oil pump timing but I'm sure someone here can fill u in

GL and have fun jumping waves!

 

[xexman44]

Thanks for the input. I will check it out. Feels funny, I've been working on 2-strokes all my life but because this one is in a boat, I feel like it's the first one I've ever worked on! Sure is fun though.
Merci!

 

[Waterluvr]

Thanks for the input. I will check it out. Feels funny, I've been working on 2-strokes all my life but because this one is in a boat, I feel like it's the first one I've ever worked on! Sure is fun though.
Merci!

What are the compression test numbers on the cylinders?

 

[xexman44]

Might be a big part of the problem. 1 cylinder is 90 and the other one is right at 100. Winter project I hope. Hopefully just new rings? I haven't learned enough about these engines yet. Good time to look at the reeds and the exhaust parts too. Still fun...so far.

 

[Waterluvr]

Might be a big part of the problem. 1 cylinder is 90 and the other one is right at 100. Winter project I hope. Hopefully just new rings? I haven't learned enough about these engines yet. Good time to look at the reeds and the exhaust parts too. Still fun...so far.

That engine is shot. You might have gotten lucky and the bottom end avoided the hot gasses and melted alloy from the pistons but it's not likely with numbers so low. You'd have to pull it apart and see, if the top end hasn't come apart to bad the bottom end could still be saved.

Either way you certainly would want to cease running that engine immediately before it let's loose and destroys the case and crank, if it hasn't already.

 

[xexman44]

Started taking the top end off to take a look at it and looks like the last guy to rebuild it JB welded the head bolts into the block. Can only get 4 out, the rest are stripping as i try to get them off with an impact wrench. The fun is starting to go away now..