Looks like the ethanol gas has finally caught up to me. While running yesterday at 3800 rpms my 98 175 evinrude 2 stroke started to get real sluggish. Then it was fine. Haven't changed the filter in a while, so I guess that is always a good place to start. But for those adding treatment to your tank, what are you adding and how much ?
I follow the instructions from what I buy, such as using 1oz of StarTron Enzyme Fuel Treatment for every 8~16 gallons of gasoline. I had a problem with the fuel system and it took me quite a while to figure it out and get it fixed. If you have a fuel/water separator, that is the first place I would check and then the internal fuel filter, then... Good luck.
Same here... Started this little project a week ago. Dumped the fuel water seperator, no water and or trash visible, changed it anyway and also dumped a bottle of Startron in the tank too. Varified fuel pressure as best as I could both loaded and unloaded, changed plugs and moved on to the VST and high pressure side Saturday. Motor would run 5 - 6 miles then sneeze, fart and carry-on and otherwise run like sh*&, but would get me back home.
Thought I had found the culprit in the VST a little build up on the high pressure intake screen, not the case.. Removed all 6 fuel injectors yesterday, guess sending them off to be profesionally cleaned/checked is my next step.
Engine is a 2002 F225, 1358 hours and otherwise flawless. Both fuel seperators changed annually. Ring Free and Stabil added every tank. Guess if this don't fix it, I will take a closer look at the high pressure pump.
Before you do the injectors…save some money........I have been fighting this for three weeks, and finally solved it. History…. preemptively changed all the filters for the spring because I had some last year fuel, and I use the startron and merc clean. While running the port engine would cut in and out after about 5 to 8 minutes of run at speed just like you mentioned. Here are my findings and additional bad issue with E10 it deteriated the gray fuel line inner lining and at high demand the line collapsed and chocked out the engine. I changed the bulb and fuel line… bingo motor ran without a single miss, but during the test the starboard one missed….so I replaced all the fuel lines with new alcohol compatible lines and bulbs, then put new fuel in because I was at 1/16 of a tank (I was going next to clean tank) ran from Kent narrows north to rock hall and back not one miss or issue, even got my Full wide open back. Now if you don’t believe it just unhook a hose at the bulb or motor and you will see the broken down liner and it will come apart into pieces of soluble plastic. Its worth a try my line was mercury gray line, and I also vent out the High pressure pump and found some water now as a maintance item I will drain the High pressure every once and a while. I started with the easy cheap components first new lines and filters then to the pumps and injectors last, but my got solved before going into the motors.
Hopefully this saves some money and others time trouble shooting… please pass it on let me know your results.