2003 yamaha f115txrb surging

[SkunkBoat]

Originally Posted by 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

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.