Blowing Black Smoke After Carb Rebuild

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Guys,

I just had my carburetor rebuilt by Mark at Mark's Offroad. He's been an excellent resource for my '78 FJ40 by the way. I took my carburetor to him, because my idle would get very rough on steep inclines.

During the rebuild, Mark discovered that there was a bracket/washer that was installed incorrectly, and was preventing my power valve from opening on zero vacuum. I believe my float was also adjusted incorrectly before Mark's rebuild.

After the carburetor was rebuilt, I bolted it on and reconnected all vacuum hoses based on the Toyota Emissions manual. Now I notice a lot of black smoke coming out of my exhaust when I let off the gas pedal (I did not blow black smoke before the rebuild). I get the black smoke on both soft and hard acceleration. I played around with the mixture, idle, and Throttle Position adjustment screws with no luck in stopping the smoke. My spark plugs are pitch black now.

My power valve port on the carburetor (marked #1 in photo below) is directly connected to manifold vacuum, and I can hear the power valve moving up and down when I release and then reapply manifold vacuum to the port. My rpm also drops slightly when vacuum is applied to the power valve port. Is it safe to say that my power valve is functioning correctly then?

After rechecking my vacuum lines, I'm pretty sure I got them connected correctly, except for 3 ports which are not clearly described in the emissions manual. These are ports #2, 3, 4 in the photo below. I believe these are the spark control ports? The picture does not show very well, but I have a port in the area where #2 is pointing. Could ports 2, 3, & 4 be contributing to my problem of blowing black smoke? How should these ports be connected? From researching this forum, I've only found pictures of # 2 being connected to #3. Also, on both idle and acceleration, I did not notice any vacuum on ports # 2, 3, or 4.

#6 does not move at all at either idle or acceleration. Could that be causing my problem?

#5, the window shows the that fuel is at the half way point mark on the window while the engine is running. But the window does not hold fuel after I shut the car off. After a short while, you cannot see any fuel in the round window. Is the fuel leaking down into my intake manifold? My carburetor is also seeping some fuel as well, even though I've checked and tightened all bolts.

Could any of these things be contributing to my problem of blowing black smoke and running rich?

sparkcontrol-1.jpg
 
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Why not give Mark a call?

With the exception of the power valve, which is shut off when vacuum is applied, none of the stuff would cause it to run rich. The only external adjustment is the idle mixture, which would have no influence at engine speeds above idle.

A little black smoke during acceleration is normal. Are you sure you aren't blowing blue smoke on deceleration? Unless the carb was rejetted, the chances it would be running rich just by rebuilding it are pretty slim.
 

FJ40Jim

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The carb shown does not have a power valve port. Power valve would be located where the rounded aluminum plug is located just above #1.

If your carb looks exactly like the pic (1978 Fed spec), then the #1 fitting should connect w/ a short hose to #3. that is the HIC valve. #4 should connect to a manifold vac fitting located on the side of the carb insulator base. Note that all of the HIC fittings are slightly larger than the regular vac fittings everywhere else on the carb.

HTH.
 
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Thanks for the quick replies.

The carb shown does not have a power valve port. Power valve would be located where the rounded aluminum plug is located just above #1.

If your carb looks exactly like the pic (1978 Fed spec), then the #1 fitting should connect w/ a short hose to #3. that is the HIC valve. #4 should connect to a manifold vac fitting located on the side of the carb insulator base. Note that all of the HIC fittings are slightly larger than the regular vac fittings everywhere else on the carb.

HTH.

My carb is a 1978 California spec, so I do have a port right above the #1 in the picture which I've connected to manifold vacuum.

Why not give Mark a call?

With the exception of the power valve, which is shut off when vacuum is applied, none of the stuff would cause it to run rich. The only external adjustment is the idle mixture, which would have no influence at engine speeds above idle.

A little black smoke during acceleration is normal. Are you sure you aren't blowing blue smoke on deceleration? Unless the carb was rejetted, the chances it would be running rich just by rebuilding it are pretty slim.

I will contact Mark as soon as he opens shop today.

I'm very sure I'm not blowing blue or white smoke on deceleration. The smoke is distinctively black and smells like gasoline.
 
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If I connect the power valve port to both manifold vacuum and the EGR port at the same time, will that prevent the power valve from opening during both idle and acceleration?
 

FJ40Jim

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If I connect the power valve port to both manifold vacuum and the EGR port at the same time, will that prevent the power valve from opening during both idle and acceleration?
No, it will just allow vacuum to leak from manifold to port at idle.

It should work fine w/ the power valve port connected to a manifold vac source.
 

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