Been seeing alot of talk lately, about how critical the throttle air gap is for proper idle. Is this just on certain models / optis, I don`t see any info in my service manual about it. 2000 EFI 225 (ot165394)
Throttle Air Gap- 4 Shutter Intake (EFI)
Been seeing alot of talk lately, about how critical the throttle air gap is for proper idle. Is this just on certain models / optis, I don`t see any info in my service manual about it. 2000 EFI 225 (ot165394)
2003 Nitro 929 / 225 EFI
Del Norte Bass Anglers
Good question!
Throttle airgap is critical on ALL of our 3L EFI or Optimax engines, as it must MATCH the amount of air that the ECM/PCM's fuel delivery is calibrated for.
A word of caution: DO NOT just start "tinkering" with the throttle plate airgap, until ALL ITEMS recommended have been confirmed to be EXACTLY as specified/required!
Your earlier (4-shutter intake) EFI utilizes the UPPER throttle plate to adjust the airgap.
The BEST way to verify the airgap is correct is to:
-Verify compression, spark, spark plug condition, fuel pressure, fuel delivery (including injectors), and TPS setting are all correct.
-Connect a timing light to #1 spark plug, and monitor timing AT IDLE with engine WARM (idling in neutral).
-If throttle plate airgap is correct (and all above items are correct), your engine will idle at the appropriate idle speed, with timing in the 2 to 4 degrees AFTER TDC range.
TIMING is not adjustable, but is a key indicator as to whether the engine is running RICH or LEAN (at idle), as the ignition timing is ECM controlled (and manipulated to attain correct idle speed).
Any adjustment to the upper throttle plate airgap should be made in SMALL increments, allowing 30 seconds for the ECM/timing to stabilize BEFORE making any further adjustments.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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Don, thanks for the detailed response. Mine seems to run a little rough when in gear @ an idle, never dies but sounds like its close to when docking or trailering. Runs great other wise, I have gone thru everthing in the service manual and everything checks out with what i can check with a multimeter.
2003 Nitro 929 / 225 EFI
Del Norte Bass Anglers
You need to make sure your exhaust port on the back of the motor is out of the water when idling a EFi for extended periods. It is the port next to the water pressure port on the back of the motor. Those motors will miss if that port not out of the water.
Richard
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