Weird dysfunctional SU carb issue, rebuilt and floats reset going on 8 times now.....

[Jarvo2]

definitely running rich at idle....any chance the SMOG equipment you have installed is causing a lean condition below a certain RPM?

[mr mikey]

The smog stuff is actually unhooked at the source, only using blocked tubes to seal off any leaks, I haven't gotten around to making the blockoff plates for everything yet, as this current issue is draining every bit of mental capacity I can put towards the car . I'll get some nipples to cover all the spots, or if you think maybe the parts are internally broken and hemorraghing through to the exterior, like a vac leak thru the housings.

[Jarvo2]

Seems like something isn't flowing as it should. Here's what I ended up doing temporarily. On the air galley, a black-pipe cap fits perfectly.

[madkaw]

Have you tried to alter timing-retard it? Does it fire up easy everytime? It seems that the timing might be way advanced.

Linkage-what have you done to eliminate that possibility?

What's the history on the engine? Have you ever heard it run right, or did you buy this and started out this way?

What year car and engine?

What distributor are you running?

I have no answers, just questions:)

[mr mikey]

Have you tried to alter timing-retard it? Does it fire up easy everytime? It seems that the timing might be way advanced.

Linkage-what have you done to eliminate that possibility?

What's the history on the engine? Have you ever heard it run right, or did you buy this and started out this way?

What year car and engine?

What distributor are you running?

I have no answers, just questions:)

I thought the same thing about the timing, especially the way it reverse rotates, but it not hard to crank(actually very easy to crank).....my camaro is base timed at 18degrees advanced, so I know how an advanced engine sounds when turning over . The linkage has been checked for slack and worn joints and such, it all seems to be fine. I can spray wd40 around the throttle shafts to check for revving from vac leaks and the idle speed never changes(unless I accidentally overspray into the barrels haha). When I bought it, I was able to drive it the 2hrs to my house, but it chugged and rolled coal when I tried to pull any real hills. Tore the carbs down per the video and found a bunch of crud in the bowls, so I went nuts with a toothbrush and scrubbed all the internal components, and readjusted per the video.....it hasn't been right since. Car is '74 260z, Engine is '74 260z, carbs are '72 240z. Distributor is a "NOS/OEM" electronic ignition distributor listed for a 260z with the GM electronic control module.....it had the Crane(Allison) Fireball 2000 or whatever it's called, but it kept going thru control modules(found later that the setups are finicky when it comes to quality).

I have all the answers, except the one to my question lololol.

[madkaw]

How do you know you are close on timing? You can't check static at 1800rpm, so what advance to you show at your present idle?

Sounds like your effort needs to be somewhere other then carbs at this point.

There was just a 7 page thread with similar issues and it turned out to be timing.

The fact that you know little about this engine, someone could have clocked the dizzy drive wrong.

[Captain_Zeros]

Maybe a little off topic, but the one time I ever had reverse rotation and puking smoke out the carbs was when I accidentally clocked my dizzy 180 degrees out like an idiot... then again it wouldn't run at all that way. It seems like it runs pretty well for the first 40 seconds or so of that video, so I'm real curious what the issue is. Do you have a different distributor/ignition-module(points even?) you could try? It might be confirmation bias but whenever I hear about HEI ignition modules there is a problem involved (then again nobody ever complains that their ignition is working perfectly either.)

[mr mikey]

How do you know you are close on timing? You can't check static at 1800rpm, so what advance to you show at your present idle?

Sounds like your effort needs to be somewhere other then carbs at this point.

There was just a 7 page thread with similar issues and it turned out to be timing.

The fact that you know little about this engine, someone could have clocked the dizzy drive wrong.

I set it per the instructions for the dizzy. Set the dizzy so the rotor is centered on the #1 plug wire contact, align the dizzy to the 0 mark on baseplate, stab dizzy so baseplate mounts to engine when balancer mark is aligned with 0 mark on timing tab. Then loosen dizzy hold-down and rotate the dizzy so it's pointing at 9 degrees advanced on baseplate, then lock-down dizzy.

[madkaw]

Timing light?

[240260280z]

Hardway and I measured the height of the fuel bowl roof from the gasket surface, I think it was 3.4mm so the 23mm down from the edge of the fuel bowl becomes 19.6mm down. We set the fuel level for this and the jets had to be set a little higher to optimize.

[mr mikey]

Timing light?

No, not on the base timing setting, it said in the instructions that it wasn't necessary, because the adjustments were fully mechanical. I did use a timing light to check max advance at 3500rpm, and it is sitting on the 36 degree mark on balancer.

[tlorber]

Do you have access to any spare carbs that you could bolt on?