2006 115hp 4-stroke fuel problems

[cowboy56]

I'm having issues with my 115hp 4-stroke on a 24' pontoon.
I had some "bogging" issues when I was using local gas station fuel with ethanol and Ringfree additive, so I switched to non-ethanol about 30 gallons ago. I recently had my 30 gallon tank scrubbed and the fuel drained, replaced the water separator and fuel pump filter and changed the plugs and I still idle rough above 2,000 RPM's and can only get up to 4,000 when trying to get up on plane. I usually get up to 5,200 at WOT. It shakes as if I'm missing a cylinder. I also have a suspicious looking #4 spark plug, that after about 30 minutes had some dry carbon on it and also seemed wet. Does this sound like my injectors may be plugged or something going on in my VSL tank? I realize this can be a number of things but was just wondering if I'm over looking something simple before I need to call the mechanic.
Thanks for any suggestions and this looks like a great forum.

Mike

[rodbolt17]

after a leak down and spark test, it sounds like its time to do the entire engine fuel system.
I simply cant wait for E25 fuels.
maybe ill retire early then .

[truckrunner9]

115 2stroke doing same .

I had the same problem and i took and cleaned the carbs it dosen't boog any more it tremble under excelleration.It 2004 model im thinking about cahnging all the fuel lines .Mine also set the alarm off if you run over 4oooRPMs.I shut it down and count to 10 and starts no alarm. I have changed water pump empellor ,thermastates and temp sencers.Blows my mind you can run 3500Rpms all dAY.ANd when it idles it smooth for minute or two and it will die like it runs out of fuel have to hit choke to start it and the plugs have carbon on them but they are wet.I really think its this ETHANOL fuel.Ive herd that it eats fuel hoses .I have to check they say the lines need to be SAE J1527.To handle the ETHANOL FUELS

[rodbolt17]

the two stroke V4 and the inline 4 4 stk EFI motors only share yamaha paint, not much else.

[cowboy56]

I would quit using Ethanol right away. I was told that IF you ran the gas out, as I do every week-end and didn't let it sit idle for months AND used Yamaha Ring Free you would be alright to use E10 but I think it came back to bite me. I had no warning what so ever. The boat ran fine and the next week-end it bogged down when I throttled, so I dumped the water separator in a jar and noticed the bottom 3/4" was this red stuff. I put on a new separator and have trouble ever since.
My neighbor uses only non-ethanol and he adds Lucas Injector Cleaner in every tank. I hate to starting adding stuff yet but some folks swear by Seafoam for cleaning problem engines.

[rodbolt17]

add all the snake oil you wish.
the stimulous fuels are still gOOOOOD.
sarcasm intended.
E fuels,like wind turbines are a BOON DOGGLE.

[estrombeck]

I have had this issue with our 225 4 stroke. I too was blaming the fuel which we go through alot of. My problem turned out to be the very small, easily clogged filter screen at the bottom of the high pressure pump inside the VST. Cleaning or replacing it is easy once you get to it. Getting to it is not for most people. Yamaha mechanic is highly recomended. I've had to clen mine 3 times in the last 7 months. Turns out some fuel lines -post filter - were breaking down and clogging this screen.