I have a 51 shoebox with flathead V-8 running dual carb setup. I have noticed that at around 1000 RPM only the front carb is dumping fuel from the emulsion tubes. I recall that when rebuilding the carbs one carb had more holes in the tubes than the other. Could this cause my car to run on one carb? Any thoughts?
LOTS of things to consider. I ***ume you are looking down the carbs as you rev it in the driveway, not while clinging to the engine under full acceleration on the road...send us the youtube link if I'm wrong. That means, since engine is not producing any power except that consumed internally to make it turn over at 1,000, conditions don't mirror anything much out in reality. Now...is this a hotrod dual with carbs over ports, or a decorative dual with one carb in about stock location and one shoved back into a different zip code? If the latter, think about the implications under a condition in which not much air is needed. Air likes to take the easy direct road... Second, remember that your carbs cannot deliver gas through the main circuit (emulsion tubes, main jets) until enough air is moving through to produce a significant pressure drop to pull fuel into the venturies. At low speeds on the road you are running on the idle and off-idle circuits down in the base. So...the difference could simply mean almost all air is going through the better placed carb, OR it could be a difference between carbs, like one has a slightly higher fuel level in bowl. I think full ****ysis here is utterly impractical in a driveway, and you should tune car by how it feels on the road and by looking for any differences in plug color beteen cylinders. Also, if using little chrome air filter, be aware that many of these are very restrictive and act like chokes! Probably ALL become very restrictive after some miles, as area is very small. Tune the car with those things off until engine is happy, THEN install them. If anything changes, you need better filters!
What Bruce is saying is spot on! to simplify it and check and equalise the airflow through your carbs is even i use a unisync, release the linkage sync the carbs and put the linkage back on.I have a dual edmunds that has the generater in stock position and the second carb is way back and the front carb is an air pig! Johnny
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