I was using my ski last weekend. We put about 9 hours on it. 5 in the ocean and the rest in some back bays. Towards the end of the ride the the GTX-DI lost power. It almost seemed like a plug was bad. Max rpm was about 2,500. It also idled more roughly than usual. Both plugs were black. One was wet and one was dry. The engine is also smoking more than normal. Blue smoke. I changed both plugs and there was no change. Both plugs have spark.

I have not done the compression check yet. I will be doing detailed trouble-shooting this evening.

One symptom that I did identify with limited trouble-shooting in the water seemed unusual. When the engine is idling and I pull the mag plug the rpm drops and the engine vibrates. When I reconnect the MAG plug the engine returns as you would expect. When I pull the PTO plug then rpm drops and it vibrates but not as much as the MAG plug. When I reconnect the plug the engines surges about 1,500 rpm for a couple of seconds then settles down to spec.

I am making the assumption that the surge is due to fuel excess in the cylinder from the injector building up in the cylinder when the plug is disconnected then being burned when the plug reconnects.

Has anyone seen this set of symptoms before?