2003 yamaha f115txrb surging

[steplift20]

I am having an issue at low and mid range with surging. Top end she runs like a champ. Coming off of plane and low idle, she surges. I inspected spark plugs, coloration all the same no signs of lean mixture poured gas from water separator in glass bowl, no visual debri, checked oil level and coloration , looked good. traced a blue and yellow wire located under the throttle linkage under cowling to the fuse cover on engine. Upon removing fuse cover, a grey connector with a black jumper wire fell out. I know it fits on the diagnostic connector location ( this was the only one without anything installed ) and am not sure if I should connect it or should it be left out?
Could this be my issue?

[steplift20]

Does anyone know of a website that I can go to look at the fuse panel on my 2003 Yamaha ? Thanks for any help in this matter,

[spareparts]

Id guess its a fuel issue. Take a good look at the fuel filter on the engine, I'm seeing them crack at the mounting stud on top. They start sucking air. Try priming the bulb and look for a leak on the fuel filter

[steplift20]

Thanks spareparts I will do that I wanted to put up pics but I don't know how I thought I was doing it fight but it didn't go thru How do I get up pics ? Spareparts a grey connected with a black jumper wire fell out of the fuse box cover I know we're it goes but I'm not sure if I should connect it I don't know if it was supposed to be not connected just like a extra

[spareparts]

not sure about the black jumper, but the port for the scan tool has a grey cover, usually retained by a piece of clear monofilament

[steplift20]

I would love to post pics , how do you do that,

[SkunkBoat]

Exploded views & part#s

http://www.boats.net/parts/search/Yamaha/Outboard/2003/F115TXRB/parts.html

Have you tried spraying carb cleaner in the throttle bodies and air control valve?
see "Intake2" diagram, #10. Looks like maybe an air filter #13 on the control valve assy also...

[steplift20]

No we didn't do that but we think it's the throttle positioning sensor If we put it in doesn't look to hard, I heard it has to be adjusted, does it ? and how do I do it

[spareparts]

leave the tps alone, if you dont have the software or a voltmeter dont mess with it. unless its idling odd, the tps is probably ok. there is a chance it could have a dead spot, but its hard to find,. You can try this trick, with the engine running and the cowl removed, tap on the computer with a screw diver handle, not real hard. See if it changes te way it runs. F115 computers are known to give issues.

[steplift20]

It is idling odd, at mid range and low range like putting it on the trailer ,( high range is fine, ) but what your saying is I do need to adjust it the tps I will tap on the computer to see if it does change

[THEFERMANATOR]

You can pick up a cable and software off of ebay for $120 I believe I paid. If you were closer, I'd hook it up for you. I'm not sure if I could copy my disk, but I've heard you can find the software online to download, then you get a usb to obd2 cable, and make 3 jumper wires to connect it(I opted for the premade cable because I wanted it to be a clean connection).

[steplift20]

Ferm thanks for the offer, I'm not to good with computers I live in nj Northern part, the problem is if I bring it in to a marine mechanic you know it's going to be very expensive, it always is and the issue I'm having is pointing to the TPS

[SkunkBoat]

Ferm thanks for the offer, I'm not to good with computers I live in nj Northern part, the problem is if I bring it in to a marine mechanic you know it's going to be very expensive, it always is and the issue I'm having is pointing to the TPS

the air control valve controls bypass air when the throttle is closed or near closed.
The computer adjusts the open/closed timing of the valve by looking at the intake air pressure(there is a pressure sensor there) From my experience on my suzuki, your symptoms are exactly what happens when the iac valve isn't working right.

If I were you, I would do the simplest things first...
1- remove the air filter on the valve and see if it gets better
2- spray the crap out of the throttles and the iac valve(remove the hose and really get in there) and see if it gets better.
3- clean the contacts of the plugs on the iac valve and the air pressure sensor

If none of that helps, you need diagnostics. You can't just start replacing things because they will require adjustment. Your best bet is a Yamaha dealer who will find the problem fairly quickly and fix it. You are going to pay for his expertise, his software, his ability to try a part he has laying around... That will probably be cheaper than buying software, a connector, and maybe not the right part(s).

I don't have a Yamaha and I'm not an outboard mechanic but I did stay at a Holiday Inn....
Are there no blinking indicators on your Tach that might be telling you what is wrong?
I was lucky, the Suzuki flashed a code that pointed to the IAC valve timing.
The Service manual($7 download) had an adjustment that could be done without a computer.

[THEFERMANATOR]

Ferm thanks for the offer, I'm not to good with computers I live in nj Northern part, the problem is if I bring it in to a marine mechanic you know it's going to be very expensive, it always is and the issue I'm having is pointing to the TPS

Tps can cause surging, but so can any of the other sensors on the engine. Pull a $100 bill out of your wallet, light it on fire, if this doesn't bother you, then by all means start throwing parts at it. If it does bother you in any way, pay the money and have it scanned. Way to many engines become projects and end up sold or parted out because people started guessing saying this part points to it, or that. Seen it happen too many times, and don't like seeing it.

[steplift20]

Ferm I understand and agree with you but it seems like every time (2) times I took it in it was a grand And I have to take it to a yammi dealer I don't mind paying just be fair I'm thinking hook it up to a computer part is probably less than 100 a hour putting it in should not be more than 300 But I know it's going to be a lot more I'm not a cheap person but dam

[steplift20]

Well, I opened up the wallet and dropped her off today, thanks for all the advice but it came down to just bringing her in,,,,, those dam computers I will let you know what was wrong when I get her back Thanks again guys

[steplift20]

I was just told that the air I'd le control valve needed to be adjusted, they said it is not bad just not in adjustment and that should take care of my problem, thanks to all for all the replys You guys are the best

[THEFERMANATOR]

I was just told that the air I'd le control valve needed to be adjusted, they said it is not bad just not in adjustment and that should take care of my problem, thanks to all for all the replys You guys are the best

Um, it's not adjusteable if it's anything like the bigger yamahas I've worked on. Most likely it was carboned up, and they cleaned it.

[spareparts]

yea, I was going to say the same thing, how ever, theer is a trick used to get them to idle better by resetting the throttle plates to put the IAC in a different range, Ive never had a need to do it, but Ive heard of others doing it. It puts the IAC in the 40-60% range rather than the 80-90% range. That still shouldn't have anything to do with the above idle surging, unless it was sticking open

[steplift20]

Still no good, dropped her off at the shop in the water, they will have to duplicate the issue on the water hopefully that will solve the problem

[steplift20]

I was just told that a code for the pulse coil came up ,does that sound right to you guys?

[spareparts]

they should have found the pulse coil issue with a spark check on the first trip

[steplift20]

They said there was a error code for the pulse coil and they cleared it but it came back, do you think that would cause the problem I am having? At no wake speed the RPMs seem to jump/serge hi speed is good

[steplift20]

Update/ we took the boat out Saturday ran it all day like normal, fishing and cruising from 9 am to 130 pm And no issues they ran it before us too for one hour and no issues they cleared the error code before they ran it also , so do you think it would be good or should it act up again? And if it does act up you know it's going to be in the worst spot for us, What do you guys think? And yes we went fishing and got some weakfish yep you heard right weakfish Thanks for any replys