65 Riv - Accelerator pump working as it should?....

[moran75 17]

Hi all

 

Want to learn a bit more about the workings of the accelerator pump...

 

Running a 65 riv with original carter 4 bl AFB.

 

Engine warm, but turned off - work throttle by hand and I see two nice jets of gas squirted into carb so Acc pump seems good.

 

WhenI try same thing with engine running and in park there are no jets of gas - though engine revs/sounds good.

 

Am I right in saying this is normal and somehow when engine is in D and actually driven,  the jets ‘do their thing’ upon initial acceleration? Maybe the vacuum facilitates this?

 

The reason I’m  investigating is that I have a ‘bog’ spot when pulling away, but only when pulling away - my money at the moment is on the vacuum advance but that’s another story - at this point just want to learn a bit more about the pump and to confirm my conclusion that it’s working OK based on above tests .

 

Thanks in advance

 

Kev

[carbking 608]

It isn't normal, and (no offense meant) do not see how it can occur.

 

Is it possible the pump squirt is there, but the vacuum present when the engine is running pulls the squirt through such that you do not see it? Again, possibly repeat this test with a couple of observers with younger eyes than mine watching.

 

Lots of possibilities causing bog. Top ones:

 

(1) electronic distributor conversion

(2) vacuum advance defective

(3) timing out of adjustment

(4) idle adjustment TOO RICH

(5) accelerator pump not functioning

 

One other which is very remote, but can occur: missing or incorrect pump discharge valve.

 

Jon.

[moran75 17]

Aha...see what you mean, maybe because if vacuum it’s more subtle...

 

will double check ....