Maybe the Webers froze up??

Started out this morning with early temperature in Tennessee at 30-32 degrees. The first several minutes of my drive to work is on back roads with traffic, so the engine has time to warm up. I hit the interstate and brought the car up to 75 MPH and ran at a constant speed for 5 miles, Then I noticed it started to bog a little and sneeze through the carbs while under light load (Weber 40IDA3C's). At the first traffic light, it seemed to be ok and at lunch (temp now 60 degrees) it seemed fine and ran great. The 2.4 has headers, so not much heat gets up to the top of the engine.

I have noticed condensation on the throttle bodies on occasion from the cold air flow. Could they have frozen up this morning?

Jack McAllister

Dunno about the Webers, but my Ducati carbs would freeze up ALL the time if it was below 40 degrees and humid...

Jack, sounds like classic carburator icing. The venturi effect of the intakes on the webers make them more prone to icing then other carbs. Hmmmm, wonder if you could adapt Aviation carburator de-icers to a Porsche?

Kurt V
72 911E

That is why the 356/912 engines had the ducts from the heater boxes into the engine bay with a thermostatically controlled flapper valve! when the air was cold enough the flaps would remain open allowing carb de-icing air into the engine compartment; as the air warmed up the flaps would close and cut off the hot air! not great for performance; but functional

I do not know if the early 911's ever had something similar, but I imagine they did!

Thanks to all for your help. I too, thought about the old "carb heat" control on airplanes.

Fortunately, warm weather is on the way to Tennessee...

Jack