Broken Idle Mixture Port?

Fu Manchu

Fu Manchu

New Member
Greetings,
I have a 1979 GMC Jimmy, stock 350, edelbrock 1406, non emissions. It was running fine after a tune up and then one day I went for a country drive on a hot day and it started idling poorly. I checked for vacuum leaks, etc. Rebuilt the carb (soaked for 24 hours, cleaned, blew out holes with compressed air, made sure things were within spec, made sure gaskets were on the right way). Didn't solve the issue. I did notice that the driver's side idle mixture screw wasn't having any effect when turned in or out completely. I took it apart again and blew out the idle mixture port with compressed air, totally clean. Put it back together and same issue. No fuel from driver's side idle port. Took it to the shop and they said carb is bad and I need a new one.

I've never had a 1406 go tits up like this under normal conditions. How/why would this happen? If I can get compressed air through the hole why won't fuel flow? Can it be fixed? I guess I don't understand the manufacturing process well enough to answer that, any input is appreciated.

Cheers
Fu
 
You probably sucked some old dirt from the gas tank along with standing water.
Take the Eddy carb apart again.
Chase the Emulsion tube holes with a fine copper wire.
Use a Stranded #10 & #12 wire 1 foot long stripped of insulation.
Use 1 standed wire and push it through tiny holes to dislodge debris.
Follow up with Carb cleaner and compressed air.
 
The other way is to use toliet bowl cleaner in a bucket.
Dont recommend.
Will eat up aluminum fast and discolor.

A large ultra sonic tank cleaner be ideal.
Good ones are $300-1000.
 
Fu Manchu said:
Where are the emulsion tube holes exactly? I only cleaned/blew out the port hole with cleaner/air. I'm not sure where the emulsion tube holes are, can you clarify or point me to a diagram? I have read http://garage.grumpysperformance.co...on-and-correcting-a-rich-edelbrock-carb.1820/ and it was full of good information on my carb, but didn't go into detail on this subject.
Click to expand...
In the upper air horn assembly that lifts off.
You want to clean the idle down passages too.
 
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