Yamaha 2003 F115 high idle problem

[Three Rivers]

I had a jack plate installed on my boat a few weeks ago and told the guy I was only getting around 5200 rpms and 36 mph on gps on Xpress X17. He adjusted my throttle cable to give me more top end. Now my boat is idling at 2000 rpms even after I adjusted the throttle cable back to its previous position. My ISC rattles after I shut the engine off. I'm at my whit's end. Any help would be greatly appreciated.

 

[rejesterd]

I would get the service manual and perform a proper linkage adjustment. The manual will suggest other possibilities for a high idle condition, but it's hard to assume it's related to the TPS (or other electronic components) if the only thing that has changed is the position of the cable.

 

[Three Rivers]

Thank you for your response. I do have the service manual and adjusted it the prescribed method. The throttle control lever is aligned with arrow when in neutral. Would it be possible for the ISC to be defective even if I hear the rattle when shutting off the motor? Again, thanks for any suggestions!

 

[rejesterd]

The ISC could be stuck, sure. But you'd have to remove it and disassemble it to really know. The manual tells you how to do that. I would also test the spark plugs. If brand new plugs can't jump the gap specified in the manual, then it could be a bad ECM (which would be consistent with your lack of top-end speed).

 

[Three Rivers]

I will check both the plugs and the ISC. Hopefully, it's not the ECM.