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Discussion Starter · #1 ·
My f115txrb has a problem with #2 cyl.I just did the usual oils,plugs,and filter changes.The motor has 560 hours and has been a GREAT engine for me.Every time I change the plugs I test the compression.Every hole had 220 psi !!! I took a mech stethoscope and checked each injector.They all sound the same(click-click).Next I pulled each spark plug off ONE AT A TIME and they all made a difference EXCEPT #2.My diagnosis is either a plugged injector or a defective coil.I will be putting in the shop monday for warranty work. I talked to Bret B. (big wig at yamaha) and he said to give him a call and let him know what dealer I took it to so that he can make sure that it is taken care of.

I will give you a follow up report on the outcome.I have a six year warranty on the engine and I keep ALL my receipts/service logs !!!! I never cut any corners.


Bobby Allen
 

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I will be interested in what is wrong with it since I have two 115 Mercs which are Yamahas.
 

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Just had my injectors cleaned as my #4 Cylinder was not firing. Haven't had it out to test it yet. Just to let you know I was told that this is caused by the new gas and it is not covered under the warranty. Good Luck. I'm very interested in your outcome.

Ralph
 

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I have a pair of 115 YAMAHA's with over 800 hours and the only problem I've had was way back in the early hours was a loss of oil pressure. It seems that the gears used in the oil pump were made from nylon, they wore and the result was a loss of pressure. But recently it seems that I have to run at a higher RPM (5000+) to maintain a speed around 27MPH. Usually I could reach that speed with about 4700. Any ideas? I do keep it in the water and the bottom is clean
 

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N2, I had a similar issue with my Yamaha recently. Had good compresion, getting spark (found out the hard way) Pulled the carb for that cylinder the main jet was clogged. I know you have an EFI but if it's got comp and spark (on time) it has to be fuel.

John, you been killing YF's up there?
 

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John's Addiction:

Did you recently fuel-up, i.e. heavier displacment. Were you fighting oncoming seas/wind? What about your trim &/or trim tabs? How about your fuel/water separators?

Could be a variety of things. I too notice a several hundred RPM shift every now and then depending on environmental conditions etc.

You probably thought about all of these, so regrets if duplicated.
Evan.
 

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Hey Steve! All I will say is that I am still learning. I did just buy a 2006 17 Carolina Skiff to help me explore the "shallower side" of Roanoke Is. Took it out yesturday way back in the marsh and was very impressed on how that boat made it thru some tight areas. I guess I'll really be impressed when I actually start catching fish:D I can see myself using the Skiff much more than the Grady.

Evan, Yep thought about all of those. I was just thinking could it be an injector problem, but my fuel management system doesn't really show an increase in GPH.
 

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One more idea?

John,

I would check your prop(s).......
Wear can cause a reduction in diameter, smaller diameter = higher RPM for the same speed or if you have hit anything that would change the cup in the blades?

Other possibility, I hope not :eek:
Water intrusion into the hull as a result of gel coat damage or a bad thru hull fitting. Increased weight, decreased speed :(

I have gotten a lot of reports that ethanol fuel reduces MPG on the highway, one would have to conclude it somehow changes the amount of energy produced in the the combustion cycle. Guess reformulated gas would do the same in a 4 stroke boat motor :eek:

Let me see here? Fossel fuel burning, internal combustion engines are causing global warming, that will melt the solar ice caps and drown the whole human race :eek: We are forced to burn reformulated fuel to save the earth, even though it caused millions of engines to run improperly increasing pollution. And oh yea! The new mix is less efficient so we have to burn millions more in order to produce the same amount of energy :confused: :confused: :confused:

And..........I'll stop now, sorry for the rant, hope you find a simple (inexpensive) solution to your problem ;)

When the new fuel started I drained my tank and started with just the new fuel. And use both carbon guard, and Amsoil fuel treatment on a regular basis. Also add stabilizer if I don't plan on using her more that 30 days. I have been pretty lucky so far, my 115 yamme 4X also has about 600 hours on her now. Best motor I've ever had :D

Stay Safe,
Joe
 

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Dont forget to change thermostats- My 115 2000 Yamaha had a bad thermostat last year which allowed gas into the oil.

Turned out okay but I thought motor was gone when I checked oil level. Also going through a problem with props. The stock yamaha prop seems to be best.
 

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I run a fuel injected EVINRUDE which requires the plugs to be indexed toward the injector or it will skip at that cylinder. Not for sure about the YAMAHA but its just a thought.

Chad
 

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I have 2 F115 yamaha's and I had a very similar problem. The one engine did not have any power. I pulled the plug wires on each cylindar and listened for a change in sound. The motor sounded fine When I pulled 2 of the four plug wires. It wanted to die when I pulled one of the remining two. This lead me to believe it was one of the power packs on the motor. Each pack controlled two cylindars. I duplicated problem on other engine by disabling one of the power packs and got my answer. The problem is that it is difficult to diagnose on land because you need pressure on the motor to tell if it is bogging down or not. Motor runs fine on land with 2 cylindars.
 

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Discussion Starter · #12 ·
As far as the comment on the the injectors not being covered under warranty because of the 'new' fuel. In the factory manual it states that ethanol fuels up to 10% are ok to use.
The newer plastics and rubbers(hoses) are made with materials that will lot leach(break apart).
I have read AND followed ALL recommendations in the manuals.Furthermore,if Yamaha new they had a problem with the 'new' fuel then a bulletin should have been sent to EVERY owner of such engine.Much like if you have a recall with your automobile.
What dealer refused your warranty work if I may ask.If you dont want to broadcast it please call me.

Bobby Allen
757-418-1966
 

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Discussion Starter · #13 ·
I use yamaha ring free and a quality fuel injection cleaner on a regular basis.The boat doesnt sit for long periods of time.I fish as much as I can.(2003 with + 560 hours)
The entire engine has the best amsoil in it since it had 80 hours on it.
 

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Bobby, the answer that I received was that if the injector was broken then it would be covered, but with it only being clogged then it was a maintenance issue and that is not covered. Good luck with yours and let me know what happens.

Thanks,
Ralph
 

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Interesting. I have a set of Yama 115's that are 2003 motors. I was coming in one afternoon and the port engine started missing real bad. Limped in. Lots of fuel in the oil, mechanic said it was from a plug fouling, #3 or #4 or both (apparently they had never been changed). When the plug stops firing, the cylinder gets cold, then the computer keeps pouring in fuel. I imagine that if the thermostat failed, it would do the same thing. He changed oil, plugs, etc. and now it runs fine again.... less than 400 hours on the motors, but I am the second owner. Not sure what the previous owner did, but it didn't look like much in the way of maintenance.
These are my first outboards, so I am learning engines all over again. Doesn't make sense to me.... ..

Roger
230SF WorldCat
 

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Discussion Starter · #16 ·
I'm going to take it to one of the local dealers tuesday or wed IF they are not back-logged.I hope that its something simple AND covered under warranty.Again,I have followed ALL the maint instructions in the FACTORY manual and then some.I have used only approved fuels.May have a boat for sale soon.May be looking at a bigger one with ZUKIS on the back.We shall see.:mad:
One dealer said they can send the injectors out and have them rebulit? Most gas injectors are unrebuildable.They are encapselated in plastic or injection molded with the electrical part in the middle.You may be able to CLEAN OR FLOW THEM but no rebuid them.Maybe I'm wrong.I've been in the automotive,HD,and marine parts biz over 20 years.
 

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Discussion Starter · #18 ·
If things dont go right I see twins in my forecast.May need to begin a life of ho'n out.:eek: Mike you look'n for a good time big boy?;) Call me.:eek:
 

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Discussion Starter · #19 ·
Yea of all times for me to have trouble with the Lady Nansea;the cows are on the move.Moo cow.....mooo.:D The reports are killn me.We tried to go a few days ago thats when she wouldnt get up on plane.:mad:
 
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