🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Carburetor throttle spindle wear causing air leak
💰 Estimated Repair Cost
Up to $120 USD
Parts and labour estimate
🔧 Tools Required
Carb cleaner spray, small mirror
📋 Overview
The throttle spindle bores wear oval with age. Air bypasses the throttle plate at idle, causing a lean condition and high, unstable idle that cannot be adjusted down.
🩺 Symptoms
- Idle too high and cannot be lowered
- rough idle
- lean backfire on deceleration
- idle mixture screw has no effect
🔍 Possible Causes
- Worn throttle spindle and bore
- throttle plate not sealing at idle
🛠️ Diagnosis Steps
Spray carb cleaner around the throttle spindle ends with engine idling. RPM change confirms air leak.
✅ Most Confirmed Fix
Professional throttle spindle bore repair or replacement carburetor.
65% of users confirm this fix worked (14 reports)
🏷️ Parts Needed
Throttle spindle repair kit or reconditioned carburetor
🔗 Other Mercedes-Benz W115 Faults
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