Idle Speed and Idle Air Control (IAC) Duty

[asalcedo]

I have done the first service to my new DF90A.

The result of the Idle Speed and Idle Air Control (IAC) Duty Inspection with the SDS tool is:

Engine Idle Speed: 688 or 719 rpm (sometimes it shows 688 rpm, other 719)
IAC Valve Duty: 28.8% (when idle speed was 688) or 33.8% (when Idle speed was 719)

The results were the same with engine in neutral or in gear

According to the manual

Idle speed in neutral and in gear (IAC duty) should be
550 – 650 r/min (Duty: Approx. 0 – 30%)

Should I be concerned that my Engine Idle Speed is higher than 650 rpm?
Should I be concerned that IAC Duty is also higher in one instance?

According to the manual

"If IAC duty and / or idle speed is out of specification,
inspect idle speed control system referring to “Idle air
control system check”.

With my limited knowledge of the SDS software, I performed what I think is the "Idle air control system check" and the engine did rev-up to exactly 1000 rpm as expected.

[boats.net]

It is fine, it engine is cold or outside temp is cold then will idle a little high.

[asalcedo]

It is fine, it engine is cold or outside temp is cold then will idle a little high.

Great, thanks.

It was certainly colder than usual (but not too much, about 48 F)

I'll leave it as it then.

I have also read now in the Owner's Manual, (not in the Service Manual), under Idle Speed Adjustment, "The idle speed has been factory adjusted between 650 - 750 r/min in neutral", which is higher than what the Service Manual that I quoted says.

Which idle speed range is the correct one?



Thanks again,

Antonio