Spenc

Just changed out accelerator pump on 4bl. Q-jet and used two gaskets under the horn. Is this why when I stomped to the floor it went died for a half second backfired then continued running? Adjustment issue now? 350 Z, no air or emissions. Runs ok other wise. Help and thanks

Galaxie500XL

iTrader: (1)

Sounds to me, based on what you describe, that the car went massively lean when you punched it.

hockeyman48

Did you attach linkage to the same hole in actuator arm? If you did,......did you check the float level adjustment when carb was apart? Those are 2 things to check. Also , it could be the secondary air plate needs some adjustment( spring needs more tension) to open a tad bit slower.

Spenc

Nice looking car. and thanks for the tips well look there.

Spenc

ok thanks

hockeyman48

thank you and you are welcome.

zed-028

any reason you used 2 gaskets under the airhorn?

correct me if im wrong but wouldnt that stuff with the metering rod hanger length? as in, youd start off with the needles already sitting higher if not off of the seats?

hockeyman48

There should be enough clearance between top of second gasket and bottom of primary metering rod assembly to not lift rods out of jets. I also doubt it would affect the secondary metering rods towards a lean condition. It may change the geometry of the accelerator pump linkage with the increased gasket thickness as you are raising the upper carb assembly.If the float level is lower than it should be.... its possible to affect accelerator pump operation. Spenc....... did you clean or replace accelerator pump ball check valve?

five7kid

iTrader: (14)

Known as "quadrabog". Secondary air valves opening too soon.

Assuming all linkages are there that are supposed to be there, check the choke pull-off - when pumped up with a vacuum source other than the engine (like a vacuum pump) and locked on, it should stay pulled in. If it doesn't, that's your problem - replace the choke pull-off.

If the pull-off is okay, then adjust the air valve spring tension.

Spenc

For now, all these ideas are on hold as the car is back in it's cold parking space. The air horn gasket was fuel saturated so the double gasket. Maybe the horn was loose. heck. Just ordered a pulse wiper motor from Get Parts U.S. Not to confident about that transaction. Thanks guys.

hockeyman48

You may want to check carb top section for flatness (use straight edge) as they can warp from over torqueing the front two bolts into manifold.This may account for gasket leak.

naf

iTrader: (7)

stacking gaskets under the airhorn will change the plunger distance for the mixture control solenoid.

won't cause your issue but you need to either go back to a single gasket or adjust the plunger distance with the lean stop adjustment.