E10 in my fuel tank!

[bitsobrits]

In a word, no. Acceleration enrichment works just as SUs do, i.e. by a slight delay in piston movement (courtesy of the spring and oil in the damper chamber) when the throttle is opened.

[JerryL770]

Thanks, very informative and helpful guys.

I wondered as follows: If over the longer period fuel evaporated from the carbs, which it clearly does by the time it takes to fill them, if that leaves some sticky "gum" in parts, this could either prevent the dashpot pistons lifting or, worse maybe, hold the main jets up (i.e. no effective choke) until fresh fuel has dissolved this "gum" and allowed the jet/piston to move to the desired position.

Before starting, I could poke the dashpot pistons up with the lifter but not sure how to check if the main jets are dropping - maybe, lift off dashpots, pull the choke and see??

[mgcjag]

Hi Jerry.....fuel will evaporate when the weather is cold or warm......so the only difference your haveing is difficulty starting in the cold....so what changes.....battery condition,.....damp in distributor cap.....and choke. ......so everything needs to be in best working condition....so a thorough check of your carbs operating correctly, good battery etc.....Steve

[mtnjag]

The jets are moved up and down with a direct mechanical connection to the carbs with the dash manual enrichment control. So unless your dash enrichment controller is not mechanically operating the jets will move as adjusted. And of course they do no move in a driving condition once the “choke” is off.
To check their movement look at the choke linkage at the carb. If it is moving the jets are moving.

The Rods move up and down in the jet to adjust fuel flow. Your piston could stick up and prevent the needle from being in it’s resting position at start but then that would result in a rich condition without any choke operation.

[JerryL770]

Thanks Steve, the "cold" starting is not weather dependent, my car resides in a dry garage so everything is dry and the battery is usually freshly charged. The length of the cranking needed is pretty much proportional to the unstarted time period.

As Layne pointed out the jet is mechanically moved down to enrich the mixture and assuming this movement occurs I have to believe that the engine is not actually getting the required mixture for the cold start. There HAS to be a logical reason for that. So now I wonder if maybe the dried out fuel on the chamber below the jet is restricting flow up the jet (due to increased viscosity) until it is sufficiently flushed to allow enough fuel to flow. If this is the case, the best solution I can see would be to turn off the fuel pump when parked up, running the engine until it stops from fuel starvation. At that point, hopefully, the chamber below the main jet would be empty.