Cleaning Carbs - Post Clean Gauging & Inspection
Posted: Mon Aug 02, 2021 12:23 pm
Since I'm cleaning the 100th carb set this week, I thought I'd put together an addendum to the carb cleaning posts and videos showing what you should inspect and verify after cleaning so you know things are actually clean.
You want to do this on an empty carb body, before doing any assembly. You'll need a couple of strands of copper wire. I used two: One plucked from some 22 gauge stranded copper and one plucked form some 10-gauge stranded wire. These are the openings/passages you want to confirm are clear:
Main and Pilot Air Jet
Pass a wire through the main air jet:
It should come out of the main jet near the emulsion tube:
Do the same for the pilot air jet. It should come out of the pilot jet hole:
Enrichment Circuit
Pass the smaller wire through the enrichment circuit jet:
It should push through the jet about 1 3/4":
Do the same for this [maybe diaphragm differential jet?]
Pilot Screw & Circuit
Pass the smaller wire thorough the pilot screw orifice:
It should pass through and come out in near the intake size of carb the venturi:
Pass the larger wire through the pilot jet hole:
It should go in about 1 1/2":
Main Jet
Pass the larger wire through the holes in the emulsion tube. All should be checked and cleaned:
Pass the larger wire through the center of the emulsion tube:
It should come out in the center of the carb venturi:
Once you've passed wires through all these passages, blow each out with some higher-pressure compressed air or carburetor cleaner.
Jets & Brass Parts
Do the same for the jets. Pass the smaller wire through the pilot and main jets and holes:
Once those are clean and you can see light through them, use a cotton swab damped with rubbing alcohol and clean out the main jet and needle holders and the acorn nut. This is what came out of my main jet holder, even after two runs through the ultrasonic and a soak in alcohol.
You want to do this on an empty carb body, before doing any assembly. You'll need a couple of strands of copper wire. I used two: One plucked from some 22 gauge stranded copper and one plucked form some 10-gauge stranded wire. These are the openings/passages you want to confirm are clear:
Main and Pilot Air Jet
Pass a wire through the main air jet:
It should come out of the main jet near the emulsion tube:
Do the same for the pilot air jet. It should come out of the pilot jet hole:
Enrichment Circuit
Pass the smaller wire through the enrichment circuit jet:
It should push through the jet about 1 3/4":
Do the same for this [maybe diaphragm differential jet?]
Pilot Screw & Circuit
Pass the smaller wire thorough the pilot screw orifice:
It should pass through and come out in near the intake size of carb the venturi:
Pass the larger wire through the pilot jet hole:
It should go in about 1 1/2":
Main Jet
Pass the larger wire through the holes in the emulsion tube. All should be checked and cleaned:
Pass the larger wire through the center of the emulsion tube:
It should come out in the center of the carb venturi:
Once you've passed wires through all these passages, blow each out with some higher-pressure compressed air or carburetor cleaner.
Jets & Brass Parts
Do the same for the jets. Pass the smaller wire through the pilot and main jets and holes:
Once those are clean and you can see light through them, use a cotton swab damped with rubbing alcohol and clean out the main jet and needle holders and the acorn nut. This is what came out of my main jet holder, even after two runs through the ultrasonic and a soak in alcohol.