I just returned from my 2nd test drive of Veronica, my son’s ’69. About 2 hours at 100 kph with air temperature in the mid 30’s C. After pulling into my driveway I popped the hood to check the atf level and to my horror found gas gushing out of the vent tube of the front carb. The carbs are HIF6’s on a B20.

Now for some history. Last November, shortly after acquiring the car, I noticed that there was gas seeping out of the bottom of the float bowls on both carbs. I replaced the rubber rings, which were shot, indicating to me that there had been no recent service activity. Based on this, I decided to replace the needles & seats as a precautionary measure. I bought replacements at Lordco. I should have been more suspicious at that time since the replacements were two piece – separate needle and seat, whereas those in the carbs were integrated, with the needle and seat together as a unit. Almost immediately after installing these new needles and seats and starting the car, the rear carb commenced leaking profusely. The front carb seemed fine. I swapped the old n&s unit back into the rear carb and left the front carb with the new n&s combo.
Based on this experience, today I swapped the old n&s unit back into the front carb and started up the car. Immediately the rear carb started to leak! I goosed the engine a tad and it quit leaking. My theory is that the additional engine vibration freed the stuck n&s in the rear carb.
Left to my own devices, I would replace the n&s in both carbs with genuine SU parts. However I’m concerned that I am missing something. As an afterthought I should add that prior to all this, the gas tank had been boiled out, the fuel pump changed, and the post pump filter changed. Is residual gum in the system a possible culprit? BTW, throughout this entire saga, the float levels were as close to spec as I could make them.

Thanks,

Barry