86 Nissan PU -Hitachi Carb bubbling gas

Starts fine but runs rich then stalls out. I pulled air cleaner cover and restarted and saw gas just bubbling out of the front section of the throat referred to as the air vent in Chilton's manual. I just had this carb professionally rebuilt thinking that a rebuild would solve the problem, but this is the same problem I had before the rebuild. Can anyone tell me what could be causing this?

Reply to
Budroo
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It must be a bad summer for Nissan carbs. Mine won't idle. If yours is spitting gas out of the top of the carb and into the air filter housing, I'd suspect a blockage in the exhaust system. If exhaust can't get out the tailpipe, it will start OK but as pressure builds in the exhaust it will run richer and richer until so much pressure builds up that fuel gets pushed back past the intake valve and through the carb. Are you getting a nice flow of exhaust out the tailpipe? You might put a vacuum gauge on a vacuum hose connected to the intake manifold. The hose from the PCV valve to the valve cover is a good one to try (assuming the PCV system is working correctly) as it is easy to reach. You should see a nice steady 16-18"Hg. If it's bouncing wildly and occassionaly reads positive pressure instead of vacuum, you know the problem is downstream of the carb and is likely an exhaust blockage. A logical place for a blockage is the catalytic converter particularly the perforated screens at either end of the cat. Good luck. Al

Reply to
al

If your 'rebuild' shop didn't install the float or needle correctly, the bowl will overflow and enter the throats thru the vents. Have you checked the fuel level in the bowl?

rock4arolla

84 Nissan KingCab 4x4
Reply to
rock4arolla

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