360 engine

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Bills70 said:
but the engine does want to keep running, some times, when I shut her off!
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Possibly retarded ignition timing and thus the throttle plates too much open to compensate, and that allows the 'dieseling' (run-on). Cheap fuel too.
 
nm9stheham said:
Possibly retarded ignition timing and thus the throttle plates too much open to compensate, and that allows the 'dieseling' (run-on). Cheap fuel too.
Click to expand...
I am pretty sure timing is correct, I am "not" sure that throttle plate is not to far open, could I have my idle a bit to high? I run unleaded premium!
 
What is meant by 'correct' here? If stock, per the factory, that may not be good enough. Stock timing in the smog era engines was retarded for emission purposes and that, plus higher temp t-stat's (also for emissions purposes) resulted in dieseling becoming more and more of a problem. Anti-dieseling solenoids were added to many carbs as a band-aid to fix this.

The other thought is that the secondary stop screw is not set right. That may force you to set the primary too far open and allow the dieseling problem.
 
nm9stheham said:
What is meant by 'correct' here? If stock, per the factory, that may not be good enough. Stock timing in the smog era engines was retarded for emission purposes and that, plus higher temp t-stat's (also for emissions purposes) resulted in dieseling becoming more and more of a problem. Anti-dieseling solenoids were added to many carbs as a band-aid to fix this.

The other thought is that the secondary stop screw is not set right. That may force you to set the primary too far open and allow the dieseling problem.
Click to expand...
I set the timing where engine was dynoed at! my engine builder put a mark on the balancer and I set that approx. 3000 rpm to "0" which is about 12 degrees at Idle! I will see if I can find a secondary stop screw on my Quick Fuel SS750 carb!
 
Roger.. not stock. So that solves that question! Tnx.

Look on the passenger side, underneath.
 
Each time you adjust that, you'll have to re-adjust the primary side and mixture. If the secondaries are too far closed at the stop, you would have to open the primaries more and fuel can get pulled from the primary transition slots at idle. If the secondaries are too far open at the stop, then it can allow fuel to be pulled in from the secondary transition slots at idle.

The starting, initial setting is so that the lower ends of the secondary transition slots are just enough exposed to a square shape below the secondary plates when they are closed. Then you adjust from there. (We had to close the secondaries a bit more from that for a 340 with moderate cam and 600 cfm carb.)

When it is right, you have command on the idle mixture with all of the mixture screws.

Let the real tuning begin....LOL
 
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