Hi All,

Working on a 1987 GL wagon carbureted (hitachi DCZ-328) ea82

Longtime lurker here but have been searching tons and not found a great answer to this. Can someone send a photo of where the secondary gets its vacuum from? I have rebuilt the carb, cleaned and cleaned and reinstalled but having the same issues I have always had, no low end power, and bogging when you punch the gas. Accelerator pump was missing the check ball and had a tear in the diaphragm so I was assuming that would be it for sure but after a new pump and ball I still have the same issues, now I am switching my focus to the secondary as it doesn't seem to open until very high RPMs, however I can only test this when I am standing over the engine and not during actual driving. Any help here would be greatly appreciated. Thanks.

P.S. Someone has clearly been into this thing before so I'm not sure if it's even really hooked up right, car is drivable but just barely.

 

Secondary diaphram gets its vacuum from the primary venturi.

More primary airflow = more vacuum.

 

You will have a hard time getting it to move w/no load on the engine.

I've got it hooked up right then I guess, the diaphragm is good, and the hose is new, its connected to the venturis on the right side of the carburetor to a line that goes to little holes in both barrels below the throttle plates,as more air flows through the barrels it pulls more air to open the secondary plate more,  must be something else that's causing it to bog at low RPMs. Any other advice would be helpful. Maybe some vacuum leak I am missing, thanks for the confirmation on the hookup.

Hmmm.....

That doesn`t sound right.

If it is hooked to holes below the throttle,that gives manifold vacuum which is the opposite of venturi vacuum at smallish throttle openings.

I thought the vacuum passages were internal to the carb.

 

Sure you looking at the correct one?

Ah Sorry, I mistyped, the secondary vacuum diaphram line is hooked up to the middle section of the carb, above the throttle plates, under the jets. Its hooked to a small port on the carb that goes to two holes, one in each barrel. Seems to make sense where it's hooked up, but it's just acting like its not getting that secondary open when it needs it. Eventually it does seem to open as power returns from about 3k-5k rpm.

The secondaries only open under a load or hard acceleration. The car will run just fine without them and is even driveable on the freeway without them. Drove my Brat for months with the secondaries disconnected. If you can barely drive it, you've got something going on with the primary circuit. Plugged or leaky air bleed, jets in the wrong position, float set wrong...

Ended up being a restriction in the fuel filter, changed filters and good to go. Thanks for all the help, I never have worked on many of the carbed models.