Itinerant Air-Cooled

So no. 40 in this image fell off in North-central Wyoming without my noticing it; I drove maybe 80 miles with it that way. (There was a headwind and a lot of up/down so I attributed the poorish running to that instead.)
What exactly was happening when it was running that way, and what if any bad effects can I expect to have occurred?

That linkage helps set the choke and throttle plate for a cold start. It shouldn't make any difference if it wasn't connected once the engine had warmed up.

Tim

satchmo wrote:That linkage helps set the choke and throttle plate for a cold start. It shouldn't make any difference if it wasn't connected once the engine had warmed up.

Tim

Yes--it was definitely a harder start. Maybe the perceived lack of power was wind and grade after all? Still, when my 'repair' failed the next day, I swear it was running a little poorer. Placebo effect?

Placebo effect? Probably.

From what I remember, when the engine is stone cold and you depress the accelerator completely, that linkage lets the choke stay mostly closed and also keeps the throttle plate open a little. Once the engine is warm, and the choke has opened completely, then the throttle plate is able to close completely when you let off the accelerator, and the central idle system takes over.

I'm sure Colin could explain it more eloquently using words like cam stops and choke heating element bimetal springs, etc, but you get the idea.

whc03grady wrote:So no. 40 in this image fell off in North-central Wyoming without my noticing it; I drove maybe 80 miles with it that way. (There was a headwind and a lot of up/down so I attributed the poorish running to that instead.)
What exactly was happening when it was running that way, and what if any bad effects can I expect to have occurred?

With satchmo's touching regard for my eloquence duly noted, that thar thingamabob is the fast idle link doohickey whose only job is to crack open the throttle when the choke is on.

Now, where are the little nuts? Better not be in the crankcase . . .

You will need to adjust the link when you find the little nuts.
Open throttle a bit.
Close choke plate fully.
Adjust lower nut so that is pushing the link down enough to make a 1/4" gap between the stop screw and the carburetor base.
(your Bentley will have the procedure where you stick a drill bit between the throttle plate and the housing with the carb off the car)
Snug the upper nut down.
If idle is too fast when cold, loosen the upper nut 1/2 turn and bring up the lower nut. Check again at next cold start.
If idle is too slow, loosen the upper nut and make the lower nut push the link further by a 1/2 turn. Snug upper nut down. Check again at next cold start.
Both carbs should have an equal amount of throttle pushing when chokes are on. Read the Dual Carburetor Adjustment Procedure.
Colin

Amskeptic wrote:Now, where are the little nuts? Better not be in the crankcase . . .

Oh, the little nuts ("pintos" in Portuguese; that's why Ford didn't do too well in Brazil with that particular model) didn't fail, the big pin they straddle did. It's all worn groovedy-like, and the washer that holds it on let go. Which, caused it to bounce around until the little circlip on the bottom let go too (I found all the parts). This'd be better with pictures, right? They're forthcoming.

whc03grady wrote:

Amskeptic wrote:Now, where are the little nuts? Better not be in the crankcase . . .

Oh, the little nuts ("pintos" in Portuguese; that's why Ford didn't do too well in Brazil with that particular model) didn't fail, the big pin they straddle did. It's all worn groovedy-like, and the washer that holds it on let go. Which, caused it to bounce around until the little circlip on the bottom let go too (I found all the parts). This'd be better with pictures, right? They're forthcoming.

As a forthcoming little pinto, may I add that you can fix the link like I did on the Road Warrior by bending the lower end hard 90* and make a retainer to hold it in the throttle link. This alerted you, by the way, to the need to lubricate any piece of metal on these carbs that slide against any other piece of metal. Grease is good here.
ColinPiningForADualCarbBus