Black Smoke... (1 Viewer)

[PAFJ]

Out the tail pipe when accelerating and shifting between gears. Does not happen on decel, and also goes away once engine has warmed up, why it goes away when warm is a mystery to me. I thought it was running too rich, so I leaned it out as much as it wanted to go and still idle, but still blows black smoke. Float level is good, right in the middle while running.

This started soon after I pulled the air horn off the carb to clean out some sediment that was plugging one of the jets. Could I have done something while I was in there?

TIA-

 

[inkpot]

Howdy! If you adjusted the idle mix screws to lean it out, you didn't do any good. Those are to adjust the mix just at idle speed only. To change the mix at higher speeds you need to rejet. It sounds to me like you changed the choke adjustment when you worked on it, so now it is quite a bit richer than before. When the engine warms up, the choke is off, so no more problems. Lean out the choke and you should be back where you were before. John

 

[PAFJ]

Why would choke be off when warm? The choke is off when pushed in right? I guess its possible the choke plate is out of adjustment, but why would it correct its self when warm?

 

[2mbb]

The choke plate is connected to two vacuum actuated diaphragms, one called the choke breaker and the other the choke opener. One is used to open the choke plate under full throttle and the other to open the choke pate once the engine warms up, regardless whether the choke knob is pulled. If you have an emissions manual review the sections for these two auxiliary systems.

 

[PAFJ]

Bump....

Still trying to figure this one out. Any other input would be appreciated.

Lean out the choke and you should be back where you were before. John

How do you lean out the choke?

The choke plate is connected to two vacuum actuated diaphragms, one called the choke breaker and the other the choke opener. One is used to open the choke plate under full throttle and the other to open the choke pate once the engine warms up, regardless whether the choke knob is pulled. If you have an emissions manual review the sections for these two auxiliary systems.

Thanks for the input... The CO and CB are working as they should. Not exactly like they should in accordance with the FSM because the systems were modified a bit w/ the desmog. They were hooked up the same pre black smoke as they were when the problem started. So I'm not sure this is were the problem is.