Adding Evaporative Controls to 273 2B

Before mounting the carbon canister I installed the Holly 2280. It was a simple bolt-on using the thick spacer gasket. I also purchased longer studs to install later. I fear busting a stud before my first test. I fabricated a new longer choke rod from a steel welding rod. I determined that measurement, by measuring the BBD choke crank with choke closed, to manifold. Then repeated the measurement on 2280, using a thick spacer gasket. The difference (1/2") was then added to the choke rod.

The return spring was moved from the throttle crank peg to the hole in the 2280 crank ahead of the peg. In the stock BBD location, the throttle crank conflicted with the spring. I also loosened the throttle cable clamp and moved the cable 1/4" forward to allow the throttle to return fully. The automatic kick-down was adjusted to spec.

I connected the purge line, and bowl vent to canister and plugged the tank vent. The canister was placed out side the grill for testing the carb. The vacuum control signal not connected, canister is inactive as far as purge. The canister will still absorb vapors.

When I removed the BBD it still contained a couple table spoons of gas, but not enough for a full bowl. It had set for 5 days, so not sure if leak, or gas evaporates that fast.

With the 2280 installed, it cranked and started after about 3 seconds, to fill the bowl. I set the curb idle to 650 RPM and adjusted the idle mixture screws 1/2 turn out from the 1 turn out initial. It idled nicely, I took it for a short drive, it was very smooth and responsive. There are additional settings to do on the power valve, and linkages. Those need to be done after curb idle is set. So far there is better idle quality, and a couple ticks more vacuum on the gauge at idle. The BBD had a little bit of surge on throttle release, not preset on the 2280.

And, it did not stink up the garage!!!!

I will report back once the canister is installed, tank vent connected, purge control installed, and full tuning is done.