Vapor Locked

It’s spring, the weather is warm, rain has stopped and it’s time to be out driving.

I’ve put a couple hundred miles on the car in the last weeks; by and large, it’s running well. My nemesis, vapor lock, still haunts me though. After a longish drive, at speed, the motor refused to fire up until I shot a few doses of starting fluid into the carb. (I still don’t know why this worked, but now carry a can in the car in case of relapse.)

The Thunderbird is never difficult to spot in the parking lot.

I tuned up the motor a little more finely after that episode, backing the timing off a few degrees and raising the idle a bit. Since then, hot starts haven’t been an issue (though I haven’t yet tried to recreate the exact conditions of the last episode), but I am still experiencing rough running and stalling after long periods of idle (stop-and-go traffic) and after hot starts—classic vapor lock symptoms.

Researching the topic: EFI, electric pumps and recirculating fuel delivery systems appear to be the only real solution—none of them in the budget in the foreseeable future. Long time readers will know that I already run with a phenolic spacer under the carb to fight heat soak. Other, less costly, remedies to try include an electric fan (which I’m resisting as a matter of Thunderbird purity) and an insulated metal fuel line from the pump to the carb (probably my first step).

My tune up was inspired by an observation that the distributor vacuum advance line was plugged into the wrong port on the carb.

A friend following behind me last weekend noted that the right rear brake light cluster is not coming on when I stop. (The highway patrol officer who followed me for a while yesterday did not stop to mention this, thankfully!) I believe the issue is with the turn signal switch. I also believe I have a spare aftermarket switch in a box somewhere.

The current switch is original and was salvaged from another car when I did my dashboard swap. Frankly, I won’t be sad to see it go. The horn brush is stuck in it (so no horn) and recently it stopped canceling right turn signals (always embarrassing). If I get really enthusiastic, I may even tackle the back-up lamps (which have never worked) while I’m replacing the switch.

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