Carburettor Diagnosis

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Before replacing your carburetor, check to see if it really is bad. Perhaps it just needs correct Adjustment or the problems you have experienced are related to ignition or other causes.

How Can I Tell if I Need to Repair or Check my Carburetor?

Carb-related problems include:

• won't idle under 800 rpm
• non-steady idle speed
• engine keeps running when ignition turned off (dieseling)
• poor mileage
• stumbling when accelerating
• misses or lacks power or at high speed
• black smoke from tailpipe. Definitely a carb problem, probably the choke or power valve
• engine won't start. More likely this is not a carb problem, but some other problem
• etc.

Now, some of these symptoms can also be caused by electrical or other causes. So see the Carburetor Adjustment page to rule this out.

High Idle Speed

The A12 engine is very smooth and quiet. High idling is usually caused by a vacuum leak (unless your carburetor is shot).

Also See:

• Carburetor Adjustment
• Carburetor Repair (major service)