Carburetor secondary buttefly test???

[k91]

Hey all...

I recently rebuilt my 76' Aisan carburetor and when I put it back on the 40, I was getting huge bucking, backfire through the carb and stalling issues when I would try to accelerate. I hooked up the vacuum guage and found it had fair vacuum, adjusted the timing, sprayed for leaks and tuned the carb as best as I could at the time. I noticed however that the secondary linkage was binding up. I took the secondary butterfly linkage spring apart again and think it is back together right now. Question I am asking is, does anyone know of a way to test the secondary vacuum? I have the linkage right, now it opens the secondary when I pull the lever, just dont know of a way to test. Any input appreciated, Matt

 

[FJ40Jim]

Try putting the primary booster in the primary bbl, instead of the secondary bbl.

 

[k91]

Holy crap...technical stuff....Can you break that down in laymens terms for me? Thanks for the suggestion, Matt

 

[Pin_Head]

Booster = nozzle (some people call them venturis, but the hole they sit in is the venturi).

Technical stuff is unavoidable. Here is some reading in tech links you might have wanted to do first before rebuilding it:

Cruiser Carb Info - Land Cruiser Tech from IH8MUD.com

BTW, the problem is not due to the secondary. It should run fine and accelerate with only the primary working (but it isn't). The opening test is to put a paper clip on the actuator rod so that it touches the can at the top. It it opens, the paper clip gets pushed down the rod.

 

[k91]

I am assuming your talking about the two items pictured, one with a ring and one without? Funny thing is, the picture shows how it was installed, I switched them around because the diagram I have showed this was backwards....I guess I will switch them and see what happens...

 

[FJ40Jim]

As pictured, the boosters are in the wrong places.

Switch them and it will run better.

 

[k91]

FJ40Jim...Interestingly enough, as pictured is how I found them when I took it apart. I switched them as the diagram and you say and it runs like crap. I was not really too surprised to find them backwards, I also found that the last person in the carb left out the power valve. So I placed the primary bbl and secondary bbl in their proper places (opposite of pictured) and a new power valve during the rebuild. Any other ideas? Thanks, Matt

 

[grant5127]

How does the accelerator pump flow look?

A weak amount won't be enough to get up to the point where the main metering system takes over.......

 

[FJ40Jim]

Sounds like it still needs to get the correct slow & main jets in the correct spots, install correct power jet, correctly connect the PV vacuum, correctly connect AAP vacuum, disable vacuum retard...

 

[k91]

FJ40Jim...The rebuild kit I bought did not have new slow or main jets included, therefore, I put them back where they came from. the carburetor does not have AAP and I cant say I really know how to disable the vacuum retard...I am going to do some research and find out which jets were required for the 76' Aisan. Thanks for your input, I really appreciate it, Matt

 

[k91]

Sorry to brig this issue back to the top, but I am not able to find the problem....

One piece of information I left out was, this issue started after I had a new muffler (thrush turbo) put on the 40. Now I know that a new muffler can change compression and such, but make the vehicle run sh***y?? Any thoughts?

Matt