1972 fj40 carb

[cobrasjj]

can anyone tell me what the small arm on the right rear of the factory carb is, it has the small cylindrical counter weight on it) it only seems to be connected toi a butterfly inside the carb and nothing else. any ideas?

 

[Degnol]

It is the mechanical secondary.


Ed

 

[cobrasjj]

no, it is next to the secondary though. it appears to be a small, curved rod, not connected to anything except for a small butterfly valve inside the carb, above the lower butterfly valves. it has a cylindrical counter weight on the end, to allow it to move back to the correct position. what it appears to be to me, is some sort of "anti shock" device...or something.

 

[65swb45]

Form follows function. Stabbing the pedal at low rpm when you have mechanical secondaries results in a sudden and substantial drop in vacuum.
Since several functions of the carb rely on vacuum in the primary bore, these functions are disrupted as well. Air [and vacuum] will follow the path of least resistance.

A counterweighted baffle helps lessen the vacuum dropoff, as airfow remains better matched to actual demand.

That is the theory anyway.

Best

Mark A.