Rear engine idling high

[Tim Wang]

Hello There,
I have a 1967 Skymaster with Continental IO-360's. The plane was doing its annual inspection and sat for over a month outside before my AME touched it. One cylinder (#6) on the rear engine was replaced. Now my rear engine has developed an issue of idling too high (1500 rpm's). My AME tells me the adjustment screw isn't the issue and he is stumped.
Any idea, please let me know.
Thanks
Tim

[Learjetter]

Tim,

If the engine won’t slow below 1500 RPM, I’d first suspect an issue with throttle cable not closing off the throttle body enough.

Have your mechanic run the fuel system setup in TCM manual M-0, Ch 6 (also in SID 97-3G) and also verify throttle and mixture and prop cable travel and tensions are all set correctly.

One of the first steps of the fuel system setup is to back off the idle speed screw at the throttle body and ensure throttle can slow engine to 675-700 Rpm idle on rear engine.

Then idle fuel pressure is set at the fuel pump, then idle mixture is set at the fuel metering valve, then full power pressure/flow is set at the pump again Any adjustments at any step result in starting over from step 1.

-LJ

[Tim Wang]

Hi LJ,
Thank you for the information that you provided. I hope it will solve my problem. I'll post the results once I know what happened.
Take care.
Tim