717 sometimes runs well but more often smokes and runs unevenly

[Bowis]

I have a Sportster 1997 with the 717 engine. My problem is that sometimes (very sometimes...) the engine runs smoothly and well, and I get up at top speed without a problem. After turning off the engine and start it again, it goes up to about 3000-4000 rpm, smokes and runs unevenly. I have renovated the carburetors, replaced the neutral switch, checked the ignition timing, changed fuel filter, changed fuel lines, checked the grounds, changed spark plugs, checked compression, checked and lubricated the fuses and contacts and a lot of other things. The engine seems to get fuel when I can see it on the fuel filter. The error seems neither to depend on whether the engine is cold or hot. Sometimes the engine runs without problems but usually the Engine show this kind of problems and the boat runs not more than a few mph. The problem is both forwards, backwards and in netrual position

My thoughts are if it can be MPEM who have something wrong or if it's something with the ignition that is incorrect or has a bad connection. I do not believe that it is the carburators but you never know. A problem is that the MPEM's are not available as spare parts, otherwise I could buy a new MPEM. Replacing the ignition can of course be a solution but then I have to lift the engine because of the cramped space. Might be next step but ...

I'm stuck! Has anyone had the same problem?

Br
Bo

 

[LouDoo]

It sounds like it could be the voltage regulator/rectifier, disconnect the red lead, if the problem clears up, replace the rectifier. The rectifier, part #14 is located in the e-box. The battery will not charge with the red wire disconnected.

BTW, welcome to the Seadoo forum.

Lou

 

[Bowis]

Hi Lou

It was a really interesting tips. That I will definitely try it because I have a hunch that the problem is related to the ignition so this is definitely worth a try. I will order a regulator / rectifier and try. Thanks for the tip.

I have messed with this error all summer so I'm open to everything now. I will return when I tested (I live in Sweden so it takes some time to get the spare parts from the United States)

Br
Bo

 

[Minnetonka4me]

Yup I think he has you on the right track...considering what you said you have tried.

Also, if you didnt replace the needles and seats in the Carbs when you did the rebuilds...it could be that. Usually though when they leak, its a pretty constant problem.

Welcome to the best Seadoo forum in the world!! If I can help with anything let me know.