sleepy Posted February 9, 2022 Report Share Posted February 9, 2022 There is very little, if any, vacuum from the port (the little metal tube) of the carburetor that the vacuum line for the EGR connects to including under high rpm. I've sprayed carburetor cleaner into it. On one occasion greater vacuum returned, on others still very little if any vacuum including high rpm. In the past, the carburetor was removed and soaked in a container of solvent. This for a time resulted in better vacuum to the EGR but the vacuum to the vacuum break diaphragm was intermittent. Seems pretty certain to me that the problem is with the carburetor. Anyone know exactly how the vacuums on this model carburetor work and what might be the solution? Quote Link to comment
datzenmike Posted February 9, 2022 Report Share Posted February 9, 2022 The vacuum port for EGR and the one for vacuum advance simply goes to a port or small opening just above the throttle plate. So at idle it is open to ambient air pressure, and no EGR and no vacuum advance. As the throttle opens the throttle plate lifts up to and past the openings and some intake vacuum is applied. You may not notice much vacuum just revving in neutral because there is no load on the engine and to rev up, the throttle plate really does not have to open very far. Obviously at near to and full throttle, when the plate is fully open, the intake is practically at zero vacuum and again, EGR and vacuum advance are basically zero. Try spraying carburetor cleaner into these ports again and let sit. Then push the nozzle in as far as you can and blow it out. I have no idea what vacuum to expect at the EGR port so if any it's probably fine. Check the hose for cracks. Quote Link to comment
sleepy Posted February 16, 2022 Author Report Share Posted February 16, 2022 Datzenmike, Thank you very much for your knowledgeable reply. I'll try your suggestion as I keep working trying to figure out this monkey. All the best to you with your monkeys Quote Link to comment
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