International — Idle speed and fuel mixture adjustment (gasoline engines)
Adjustments · carburetor
From a International owner's manual covering: C-152, C-196, C-304, C-345, C-392, C-446, C-537, C-605. Check it applies to your exact model before use.
Applies to: International C 549 engine
Before you start
- Idle speed and fuel mixture adjustments must be made with air cleaner in place
- Where engine is used in a vehicle the transmission must be in neutral with the parking brake applied
- Do not idle engine continuously for more than three minutes at one time
- After each three minutes of idling, increase engine speed to 2000 rpm for one minute
Procedure
- Connect tachometer (expanded scale 400 to 800 or 0 to 1000 rpm, 1 to 2% accuracy).
- Remove limiter caps; file or grind away side of cap, do not pry cap off.
- Operate engine until it reaches normal operating temperature.
- Gently seat idle mixture screws.
- Carefully adjust idle mixture screws (equal number of turns) to produce maximum idle speed.
- Adjust curb idle speed screw to give engine speed higher than midpoint of idle speed range per specifications.
- Adjust idle mixture screw(s) in until midpoint of idle speed range specification is obtained.
- Install new plastic (service) limiter caps with tab in mid position.
Tools required
- Tachometer (expanded scale 400-800 or 0-1000 rpm) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: International owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.