Yamaha F115 issues

[rusty0369]

Ok, so I have a 2010 Yamaha f115 four stroke. I purchased the boat used and it was stored in a barn. I first replaced all fuel filters and oil. I ran the boat after that and it was a champ. Toward the end of the summer I noticed it having a hard time reaching 5800 RPM. Each time out it would loose a little more power. I put it in the local shop and was told two of the four injectors where plugged. Had those replaced and power came back. Now I'm in the start of my second season finding that I'm having the same issues again.

So here is what I've done up to this point. Replaced water filter, fuel filter and injector filters. I ran chemtool B12 through each injector using a 9V battery to cycle injector. Pumped about 4 gallons of gas out of tank to make sure no water is in the tank. Pulled all plugs, cleaned and tested. Took boat out and ran for about 30 min. It jumped up on plan, ran well at first then started running rough again. Came back home, replaced another water separator filter and fuel filter. Did find water in last separator filter so drained tank and flushed with 10 gallons of brand new gas. Cut all ends of all hoses and reconnected in case of air leak. Removed prop and ran motor in barrel of water. Motor sounds good but I'm seeing a yellow oily looking film on the water after running. Also to note, after last run in barrel, exhaust seemed to be really white but not like smoke, more like steam or unburned gas vapors.

Any help here would be awesome.

To add, all gas in my area has 10% ethanol in it. Should I use an additive to help with that?

 

[charleso]

First thing you may want to do is check compression, just to make sure that is not the issue. Next, with E10, you may have a fuel line breaking down. Replace all fuel lines. Last, get all of your injectors serviced. If injectors are not closing properly or are not spraying properly when opened, The droplets of fuel are not properly mixed with air and will not ignite clean. And yes, use a fuel aditive.

 

[rusty0369]

What's the best fuel additive that you'd recommend?

 

[charleso]

There are many, many opinions on fuel additives. I use StaBil Marine. Startron also receives very good ratings.

 

[rokwldr]

It is expensive but I use Yamaha Ring Free Plus, and never ethanol fuel. My Yammie (a freind) mechanic said to use this and stay away from E10 at all costs. If you must use E10 I would use the RF, one ounce does ten gallons. Never leave the E10 in the tank longer than 3-4 months even with any additive.

 

[rusty0369]

So I have replaced injectors, disposed of full tank of fuel and flushed with a second. Expensive but done. I also replaced all fuel filters except in the VST. I've replaced all fuel lines and removed the back flow valve at the tank. Spark plugs have been replaced "engine will run but I've pulled all plugs and rolled engine over only to not see a good strong spark". How strong should the spark be?

I'm now leaning toward the coils or computer. It'll run okay when cold and coming off trailer but after I've ran 3 miles down the lake then idle it goes back to running bad. How about the VST, is it possible this is my issue? I would think if it will idle I must have spark so I'm red neck removing that as my problem. It really acts like it's starving for fuel. My biggest issue is there is no E10 free gas around me. I'm about to go back to Yamaha and ask for a solution for this in the area of replacing the motor. 3 year is over but I'm at less than 80 hours on this thing.

If I do trade this motor in I'm thinking of going with the new Evinrude.

 

[ondarvr]

Your motor was designed to run on E-10, so pay no attention to that part of it, you don't need a special additive or new fuel lines.

​The dealer should be able to plug it in and read the codes.

The VST can cause running issues, some people report repeated problems with gunk in the tank.

 

[99yam40]

How did you drain the tank?
leaving any water in the bottom will ruin any new E10 you put in the tank.

Tank need to be drained of all liquid and then cleaned. no way to just use the pick up tube to drain as it is not sitting on the very bottom of tank(close but on it)

neither Yamaha or any other motor maker will cover anything if bad fuel is burned or tried to be burned.

testing is the way to go not throwing parts at it.
spark,timing, fuel pressure are all easy to check/test.
a laptop with software will look at and tell all sorts of things about a motor

 

[rusty0369]

I actually pulled the pickup tube out, inserted a pvc pipe with very small cuts in end to insure all material was removed. I then used a vacuum system from my work to pull on tank as I added new fuel and sea foam. I just finished pulling the VST off of it and found the suction screen dirty but not plugged.

While tooling around with it I found that three of the four brand new plugs show severe signs of carbon build up, not fouling, just build up. The fourth plug was clean and looked really good. Being a compressor mechanic I decided to drain the oil and flush cylinders with B12. Lord there was some black crap coming out of three of them. I disconnected injectors, and left all plugs out and ran three doses of B12 in it while turning over each time until cleaned out and dry. Letting it sit now for about and hour before I flush oil system and refill with new oil.

As for codes and repair shops I don't even wanna talk about that, this thing has been in the shop twice. First time was just over 1000 to replace injectors and perform hourly service. They didn't fix a damn thing and kept if for over a month. That was H&W marine in Marshall Texas, don't go there. I then took to Plano Marine in Longview. They replaced number four injector, flushed fuel system per their paper work, ran in tank for one hour. So needless to say, I'm doing the work with what I have at my disposal for the time being. If you know of a really good Yamaha mechanic with software and cables I'd be interested in talking to him.

If you know the name of the software and the cables needed to talk to the ECU I'd be fine with looking at it myself.

 

[rusty0369]

ondarvr, that gunk in the VST tank is coming from the E10. It'll draw moisture in through the vent line when the level is low causing the gunk to build up. I've delt with this in a lot of my compressors at work. This E10 crap has gotten so bad that we have started switching units over to run on natural gas to get the crap out of our system.

 

[rusty0369]

Latest update, after all that I have it running right now on rabbit ears. I decided to go cylinder by cylinder to see if unplugging injectors would make a difference. cylinder 1 no change when injector leads unplugged. Cylinder 2 through 4 engine became rough to the point of almost dying. So, I have four spare injectors and have changed number 1 twice. Still getting same result. Could it be that the fuel rail feeding injector 1 is plugged or air locked? I've vent the fuel valve on top several times but no change. Could the timing be off to the point cylinder 1 is firing at a no compression state? If so I would think the same would be the issue with 3. I'm confused as hell now, I've got spark, I'm assuming I have fuel in that cylinder but no combustion. Maybe it's a stuck ring preventing compression or a stuck valve.

I'm at a loss and sure don't feel like taking it back to a damn dealer to pay out the nose for them to look at it.

 

[99yam40]

are your spare injectors any good?

 

[rusty0369]

Not sure, I ordered three and replaced. These are the ones I replaced. Surly one of the three is good. I checked them for leak by at 300 psi. I also flushed then both ways with b12.

 

[rusty0369]

I'm just plain confused at this point. Gonna do a compression test tomorrow and hoping that's not the issue. If not I'm gonna scope meter the injector leads to make sure they aren't staying on all the time. If I've got compression, spark and fuel I should have combustion.

Will say this, I'm very disappointed in Yamaha engines.

 

[99yam40]

any motor will have problems if bad fuel is used.

injectors can be sent to a shop to have them tested and cleaned.
that way you know what was wrong with them and know that they are good to use.
mark them so you know which hole they came from.
they will send a report of as found and as left.
even check spray pattern from what I have read.

need to know if the injectors are getting the signal to open too

any sign of free water in a e10 gas tank means the rest of the fuel in that tank is junk.
the water and ethonal combine and drops out ruining the remaining fuel

 

[rusty0369]

I drained the tank, flushed with new gas then but a hot air blower in it to dry it out. Once dry I used a shop vac to get the small solids out. I also put a fuel pump on the hose at the tank and flushed the entire fuel system with a b12 gas mix to clean it. Did this all the way through the injector ports with out injectors and no filters.

Put it all back together and bam, still having same damn problem. Will do compression tests this evening to see what I find.

 

[99yam40]

Your 1st post tells about finding free water in a filter after changing filters.
That is all I was getting at

what kind of tank do you have.
I have read fiberglass and plastic tanks can have problems with e 10 dissolving things and plugging up things on the motor. Even exposure to sun light can deteriorate the E10 quickly

also if tank has varnish/build up from old regular non e 10 gas the new e 10 will dissolve that and take on the the motor to plug things .

monitor fuel pressures to see if they stay in spec and have the injectors flow tested and cleaned

 

[rusty0369]

The tank is a poly tank installed in the hull. The hoses are all Yamaha hoses and rated for e10. I forgot about the free water in the filter, sorry bout that.

 

[rusty0369]

The fuel pressure is also holding strong at 36 to 47 psig depending on rpm. Stronger at higher rpm lower at slower rpm.

I still feel like the issue is in cylinder 1. When I disconnect the injector leads I get no change in engine sound which has me concerned that I'm missing one side of the combustion diamond, fuel which IV verified pressure and voltage to the injector. Air, no chance of that issue as the other three are working. Spark, verified by pulling plug and seeing spark on all four during turn over test.

Is it possible that the ECU is holding that injector open all the time causing it to flood?

 

[99yam40]

I would think it would burn one out if it kept power on it., they are mot made to have but quick pulses
do you even know if it is getting a signal to open?

Have the injectors in question flow tested and cleaned.
they can stick open or closed I guess or partially restricted
spray pattern can get messed up too