2004 Suzuki df 225 high rpm/ back to neutral

[kawmagnum]

After a run above idle, control hangs with high idle, about 1500rpm or more). Turn off engine and smoothly shifts to neutral restart and idle fine. Run up and hangs again when bringing down to idle.
I disconnected cables from motor and control. lubed all and thought all was fine. After engine warmed up, started hanging again.Do not believe the problem is mechanical.

Just purchased boat with 128 hours and little service in 11 years. However, No water in lower. drive shaft "dry", water pump ok. Just dropped LU and replacing water pump and lubing everything up. Waiting on some parts. I have seen references to this problem, but no definitive answers.
Any help appreciated.

[BunkyVI]

High Idle

Did you ever figure this one out? I have the same problem with my 2005 DF225. I have replaced several Idle air control valves and no luck. Its not the throttle cables. Definitely an issue with IAC and computer communication.
when I shutdown the engine and restart it idles down to 650-700 RPM perfectly.

[Moonlighter]

Most likely an IAC issue. Have you replaced the IACs with after market "cheapies" or .....?