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Carter WA-1 Carburetor Troubleshooting

WA-1 Leaks Out the Throttle Shaft

Carter WA-1This could be cause by a couple of things.
The carburetor could be percolating.

A test to know if it is indeed “percolation” (heat soak): touch the carburetor bowl when it begins to leak. If it is not too hot to touch comfortably, it is probably not heat soak.

The other possibility is that the carburetor is simply flooding over. When excess gas runs down the carburetor throat, it accumilates at the throttle valve and runs out the shaft.

Check for a bad float – Heat up a pan of water just prior to boiling and immerse the float. Any hole or crack will show up with bubbles.
Float level – Check the float level and float drop.
Move the float up and down by hand to make sure there isn’t something catching, or binding.
Bad needle & seat – Dirt may have gotten into the needle & seat, which happens often after a rebuild. Check the gasket under the seat to be sure it isn’t cracked. Make sure there isn’t something under the gasket. If the needle has a viton tip, then it may be damaged by the ethanol, or could have been damaged with installing due to too much pressure on the needle.

Fuel pressure to high (new pump would especially be suspect). Test the pressure and compare with the specification in your engine manual.

Idle Mixture Screw Doen’t Make Any Difference When Adjusted

This does not indicate a bad idle mixture screw, but probably indicates there is a problem in the carburetor. Could be dirty and needs rebuilding. Could also indicate a vacuum leak somewhere. Use spray carburetor cleaner with a straw on the nozzle and spray around the carburetor mounting gasket, throttle body to bowl gasket, and the intake manifold gasket. A change in rpm is usually indicates a leak.

How Do I Know When the Throttle Shaft is Worn

When moving the shaft up and down, there should be no more than approximately 1/32″ free play. A loose throttle shaft will act the same as a vacuum leak. If you spray carburetor cleaner around the end of the shaft and the rough idle smooths out, then you may need to tighten up the shaft. This is done by installing bushings into the throttle body. Not a job for the novice.

WA-1 CarburetorOnce you take this plug out there will be a tube inside that will screw out.

Surging at idle? High speed? While accelerating?Surging = lean running, often a vacuum leak. Have the customer put his hand over the top of the carb (A/F removed) and see if it does anything other than kill the engine within 2 seconds. If not, then vacuum leak somewhere (could be carb, could be somewhere downstream).If not vacuum leak, check for blockages in the high speed. idle and power circuits.
Updated on 12/08/2020

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