After living with my slight hesitation for over a year and a half, figuring it wasn't that bad, I am now driven to get the Zenith's running perfectly after a ride in Arde's gorgeous verona coupe equipped with webers. I just couldn't believe how silky smooth and seamless power delivery is. A veritable sewing machine; better than fuel injection. I gotta think I can get the Zeniths to behave that well. So back I go into the dark rabbit hole of Zenith tuning.
My symptom is a slight hesitation (very small at idle, a non-car person would not notice it) primarily noticeable around 25-45 MPH. It's not noticeable at highway speeds. It's like a light 'coughing'.
I've replaced coil (w/ correct resistor), plugs, wires and pulled out the Pertronix in favor of points, just in case. It might be a bit better with points but it may be placebo effect. Timing and dwell correctly set. Valves were adjusted before this whole ordeal started about two years ago and I've never seen valves cause this hesitation. They don't audibly click.
Over the last year and a half I have re-gasketed and sealed the carbs and carb bases, cleaned, adjusted primary, secondary, linkages; sync'd them and tried just about every suggestion by those in the know over the last 12-18 months. I have checked for the float hanging on the gasket in the past and recall the gasket wasn't anywhere close to touching the float. I Eliminated the dribble from the rear carb at idle. Jerry's secret idle air hole test has the car run roughly when covered, which seems the correct result, right? It definitely doesn't run better when I cover the hole.
Spraying copious amounts of starting fluid on every outside surface of the carbs and base elicits no response --I don't believe I have leaks.
Here's my question. I'm troubled by the inability to actually measure the float chamber level to determine if it's correct. I once messed with the one of the floats and bent the arm slightly to try and adjust it. Could an incorrect float level cause this slight hesitation? How can I determine what the correct bowl fuel level should be so I can remove each of them and measure what it actually is and go from there. The whole washer under the ball valve thing is predicated on perfect floats...
Or am I chasing zebras and the problem is elsewhere?
Any insights? Thanks guys!
My symptom is a slight hesitation (very small at idle, a non-car person would not notice it) primarily noticeable around 25-45 MPH. It's not noticeable at highway speeds. It's like a light 'coughing'.
I've replaced coil (w/ correct resistor), plugs, wires and pulled out the Pertronix in favor of points, just in case. It might be a bit better with points but it may be placebo effect. Timing and dwell correctly set. Valves were adjusted before this whole ordeal started about two years ago and I've never seen valves cause this hesitation. They don't audibly click.
Over the last year and a half I have re-gasketed and sealed the carbs and carb bases, cleaned, adjusted primary, secondary, linkages; sync'd them and tried just about every suggestion by those in the know over the last 12-18 months. I have checked for the float hanging on the gasket in the past and recall the gasket wasn't anywhere close to touching the float. I Eliminated the dribble from the rear carb at idle. Jerry's secret idle air hole test has the car run roughly when covered, which seems the correct result, right? It definitely doesn't run better when I cover the hole.
Spraying copious amounts of starting fluid on every outside surface of the carbs and base elicits no response --I don't believe I have leaks.
Here's my question. I'm troubled by the inability to actually measure the float chamber level to determine if it's correct. I once messed with the one of the floats and bent the arm slightly to try and adjust it. Could an incorrect float level cause this slight hesitation? How can I determine what the correct bowl fuel level should be so I can remove each of them and measure what it actually is and go from there. The whole washer under the ball valve thing is predicated on perfect floats...
Or am I chasing zebras and the problem is elsewhere?
Any insights? Thanks guys!