DF 140 jumps to 3000 RPM on start up

[cajuncatfish]

I've had my 2004 DF 140 for almost a year now had have loved it but experienced my first problem today. Started great like it always has and just idled around for about 20 minutes looking for fish. Put it in neutral and notice idle was a little over 1000 RPM but did not think much of it and shut big motor off. Used the T-motor for a while then started the 140 and again high idle. Shut it off, disengaged the shift linkage and operated the throttle just to see if cable was sticking. Now the engine jumps to around 3000 RPM and revs erratically when started. No fault codes or diagnostic LEDs lit but I have not run the motor for more than a few seconds due to the high revs?

Any suggestions appreciated. Have not had a chance to pull the cowlings yet and diagnose throttle linkage, assume thats the first place I should start?

[Moonlighter]

Yes, check the linkages first. Although it's unlikely they may have moved. It is worth checking.

Idle speed is controlled by the IAC valve, and if it gets dirty or faulty it can cause high idle and erratic idle. Lots of articles around if you google on cleaning them and replacing them if faulty.

I believe that Mitsubishi makes and supplies the Suzuki OEM ones so you can save heaps by getting the Suzuki part number and googling that number and getting the Mitsubishi version, it's identical and a fraction of the price of the same part from Suzuki.

[cajuncatfish]

Thanks so much Moonlighter. I figure step 1 is check throttle linkage, step 2 is Closed Throttle Position (CTP) switch, step 3 IAC. Appreciate any other thoughts or ideas.

[cajuncatfish]

Now I'm even more stumped. Checked the throttle linkage and all looked good. Moved on CTP switch and it failed continuity test. Kept checking and realized the CTP switch was not contacting the throttle plate, hence the reason for no diagnostic code. Started the engine and it still has erratic idle, 2,500 - 3,000 RPM. Manually activated the CTP switch which dropped the idle about 500 RPM but of course now it triggererd the CTP switch diagnostic code. I cannot figure out why the throttle plate does not contact CTP when in neutral.

Now for the item I could use everyone's help on. In going back to throttle linkage inspection I found I could manually move the linkage. That does not make sense to me as I would not think I could move it without moving the throttle at the helm? Had my son move the throttle at helm and linkage did not seem to move much and did not seem to return to closed when he moved throttle to neutral. Wondering if I may have a broken cable? Wondering how that would affect idle?

Thanks in advance for anyone's thougths.
UPDATE: Yep, it was a broken throttle cable. Was not allowing throttle to close.