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Old 01-10-2018, 08:32 PM   #1
71rehab
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Black Exhaust after long rest

My 71 C20 with the original engine and QJet sat for a few months while I did some metal and paint work.

When I went to restart it I had to prime the fuel pump by dumping fuel down the carb. That worked fine but now my issue is that there is a large amount of black exhaust when it fires and it runs too rich before dying. If I manually open the clutch it will stay running.

The truck was running well, was timed and fuel mixture screws were set before resting it for a few months so i'm not sure what happened. I'm certainly no expert in dealing with carbs so I'm sure I'm missing something simple.

would appreciate any help
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Old 01-10-2018, 08:47 PM   #2
demian5
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Re: Black Exhaust after long rest

Smack the front of the carb with the plastic handle of a screwdriver a few times.
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Old 01-10-2018, 08:48 PM   #3
Steeveedee
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Re: Black Exhaust after long rest

You probably have some dried fuel making the float stick a little, if the choke is opening all the way. Two things to check; choke opening properly would be the first one. If you have a brass float, you could pour a little acetone down the bowl vent tube and let it dissolve some suspected crud. Don't do this if you don't know what your float is made of; I believe that acetone may dissolve the composition float.
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Old 01-11-2018, 09:58 AM   #4
custom10nut
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Re: Black Exhaust after long rest

Either it Dried fuel or Seperated Fuel. The 10% Ethanol fuel Seperates after about 30 days, and will gum up you "old style fuel delivery system". Put about a half tank of clean gas with a can of Sea Foam, and run it. It'll run like crap for a little bit but, it'll clean everything out. If that doesn't work, you're looking at a carb rebuild to fix your issue
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Old 01-13-2018, 10:31 PM   #5
71rehab
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Re: Black Exhaust after long rest

Thanks guys. Carbs banged and sea foam in with fresh gas. We'll see.
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