2006 Sportster 150 4-TEC Surging under throttle

[Frisbee]

My jet boat is surging under throttle.
2006 SeaDoo Sportster 155 HP 4-TEC, in great shape, 130 hrs of run-time.
It’s sporadically surging under throttle. The CanDoo diagnostic tool showed it’s throwing no codes. I’ve replaced the fuel pump and all 3 injectors and replaced the plugs; I’ve also cleaned the electrical connectors at the ECU, EFB and VCM and it continues after each action to surge. It idles fine but under power surges. The impeller/ring are in good shape, and no blockages.

So what I’m calling “surging:” at full throttle it is running more like at half throttle but then goes to full and back to half on it’s own...

I can’t find anyone who will service it and I need help. Help?
I’ve read other posts and can’t find solution. ECU??

 

[Jcmetz]

Hey Frisbee,
Same boat here. Battled this same issue for YEARS. Problem was local dealer only sold the boats but didn’t know how to work on them (mainly serviced atvs and side by sides). Boat changing RPMS like it had a mind of its own. Sometimes would be tough to get it to plane and would bog down while revving high and wouldn’t come out of the water.
Father in law checked it out and pulled the coil off each cylinder 1 at a time while running it in the water. When he removed the rearmost coil, nothing in the boats performance changed at all and that told us that it was the culprit on that cylinder. Got a coil (the long rubber thingy on the cycilnder) from a nearby marine dealer. It has run flawless since and runs like new. The marine dealer guy said that these Seadoos eat these coils for breakfast. Some change them on their PWC’s every 10 hrs. I think that’s an overestimation but hopefully that helps. Wouldn’t hurt to change them all out!

 

[Jcmetz]

Here’s a link to what the part looks like. Just double check your part # on the old coil before purchasing. For $50 it may be worth a try! Fixed my issue.

 

[Atom1234]

Same on my sportster , bad coils I just changed all three