Flooded every time I start it cold

[Canuck]

The carb is pretty shiny with fuel. Maybe an indication of too much fuel? I can certainly smell it.

[wallaby]

The tubes you found are for feeding the secondaries....they will do nothing for idle and cruise situations.

It looks a s if your carb is getting wet on the outside...and on the top. I suspect you have debris in the needle-seat assembly, or a heavy or sunken float....either way, you need to take that top off again and inspect. I would go ahead and start it for a second before taking it apart. That way you can see just how full the float bowl is when the top comes off. With the top inverted, the float should be level.

if the float is heavy, adjustments won't help. Sometimes you just need to put in a new float because it's so hard to tell if the original had a problem.

[Dtret]

I don’t think this applies to a q-jet but I just changed a brass float in the neighbors Holley. It had a crack in the seam and the float itself was filling with gas. 

[Gush's monte]

Aaron, check to make sure your primary needles are not binding open or the spring is too strong for your engines vacuum to pull them down into the jets. If they are not pulled down into the jet, running on the power tip of the primary needle would explain running rich and not idling well when cold. Also check that the gasket is not interfering and not allowing the primary needles to be pulled down.

[Canuck]

Update:

I’ve managed to get it tuned better with the help of a local car guy. I discovered my vacuum advance on the distributor wasn’t working and likely a source of a vacuum leak. I replaced that and it is better. Overall it runs good now. Starting is better but still not as good as it was before. It will start up and the choke is working. Initially runs a little on the rough side but smooths out and the RPM picks up to where it should be with the choke engaged.

When I start it cold it is rough but if I manually open up the primaries with my finger all the way it runs like it should. It should run well initially with the primaries mostly closed but that’s not the case. At least I can start it and it will not die now.

[1970mcss]

Progress...maybe it's waiting for warm weather.

[Canuck]

Tonight on my way home it was severely underpowered going uphill. The car couldn’t even maintain its speed with my foot to the floor. Any ideas?

[MC1of80]

Check the choke adjustment. May be the cause of both your issues. Also were the secondary air flaps opening? 

[71MonteCarloMD]

Aaron, do you still have the original “coil” that control the open/close the choke?  If so, might look into replace that?

[Canuck]

The choke is functioning as it should and is adjusted. The primary flap closes nicely at first then opens slightly when I start it. It goes through the choke stages after that and opens fully when warmed up. When cold the car doesn’t run great and still seems like it has too much fuel. If I open the primary flap fully with my finger the engine runs great. Someone suggested to me that my timing might be too far advanced which may be part of my problem. When warmed up the rpm seems pretty fast without the idle screw even touching the throttle suggesting the timing may need to be backed down.

The secondaries don’t appear to be working. The lower butterflies open but the top flaps are not opening when I quickly give it lots of throttle. The top flaps move freely when I poke them with my finger. I’ll keep messing with it.

I appreciate all your comments and ideas.

[MC1of80]

Aaron, check the choke pull off. You state when warmed up the idle is high without the idle screw touching. That has nothing to do with timing. The choke is still on. 

If the choke is still on when warmed up, the secondary air flaps will not open causing the condition you recently experienced. An over rich condition. 

Sounds like choke adjustment when warmed up which can also cause your rough cold start. 

[jft69z]

Makes me like the EFI even more. My Z/28 is a cold blooded S.O.B., even with the electric choke I put in a couple of years ago. More I think about it, this winter it has a date with a makeover. Already researching & gathering a parts list.

[Canuck]

I've owned mine 25 years and has always run great with good gas mileage. I can get it working right again and get another 25 years out of it. These are good carbs. 

[Canuck]

5 hours ago, MC1of80 said:

Aaron, check the choke pull off. You state when warmed up the idle is high without the idle screw touching. That has nothing to do with timing. The choke is still on. 

If the choke is still on when warmed up, the secondary air flaps will not open causing the condition you recently experienced. An over rich condition. 

Sounds like choke adjustment when warmed up which can also cause your rough cold start. 

The choke pull off is new and the choke is fully off once it warms up. The part that stops the secondaries from opening is not engaged once it is warmed up so the secondary butterflies open without issue. I'll take a look and see if the fast idle is having any impact on regular idle. Thank you!

[stangeba]

Almost 50 years on mine. I did have it rebuilt (30 years ago) because the throttle shaft was very loose and needed new bushings. They also re-colored it and rebuilt it. I don't remember who or where.

Bruce

[Canuck]

I’m certainly getting closer.

Here’s the choke engaging.

Here is the car just after starting cold

Once it warmed up I checked the timing which is set at 4 degrees btdc. When I give it lots of throttle the secondaries only open slightly and I get a quick pop pop pop sound.

[Canuck]

I just noticed in my video that the secondary butterflies aren't opening much. You can just see it at the bottom. I have a new throttle cable and wonder if it is not pulling enough.

[Canuck]

Mechanically by hand the bottom butterflies open.

 

[Canuck]

 

[stangeba]

Aaron,

With the engine off, have someone slowly push the gas peddle all the way to the floor.

See if the mechanical (lower) secondary's open all the way. This will let you know if you are getting WOT (Wide Open Throttle).

I saw some backfiring fog when you revved it up. That's not good. I suggest you pull all the plugs, open the throttle about 1/2 way and check the compression, just to make sure you don't have a intake valve starting to go.

you mentioned above, the timing is set to 4 degrees BTDC. Is / was the vacuum advance hose off and plugged when you checked the timing?

Also, is the vacuum going to the distributor attached to "PORTED or FULL" vacuum from the carb? You can tell by attaching a vacuum gauge to that hose or TEE it into the hose. Some people like PORTED SPARK, some DON'T. I use it on my 71 350.

I think I run about 8 BTDC. I was running 10 to 12 but pulled it back some so it didn't spark knock. Man, I should check the dwell, timing and look at my points, it's been years!

I don't think your secondary's (top one) will open much more that they are, till the RPM reaches much higher speed. Too quickly, and it will cause the engine to bog. That is also why the secondary's are also connected to the vacuum choke pull off, to slow their opening.

 

Good luck!

[Canuck]

10 minutes ago, stangeba said:

Aaron,

With the engine off, have someone slowly push the gas peddle all the way to the floor.

See if the mechanical (lower) secondary's open all the way. This will let you know if you are getting WOT (Wide Open Throttle).

I saw some backfiring fog when you revved it up. That's not good. I suggest you pull all the plugs, open the throttle about 1/2 way and check the compression, just to make sure you don't have a intake valve starting to go.

you mentioned above, the timing is set to 4 degrees BTDC. Is / was the vacuum advance hose off and plugged when you checked the timing?

Also, is the vacuum going to the distributor attached to "PORTED or FULL" vacuum from the carb? You can tell by attaching a vacuum gauge to that hose or TEE it into the hose. Some people like PORTED SPARK, some DON'T. I use it on my 71 350.

I think I run about 8 BTDC. I was running 10 to 12 but pulled it back some so it didn't spark knock. Man, I should check the dwell, timing and look at my points, it's been years!

I don't think your secondary's (top one) will open much more that they are, till the RPM reaches much higher speed. Too quickly, and it will cause the engine to bog. That is also why the secondary's are also connected to the vacuum choke pull off, to slow their opening.

 

Good luck!

I can get WOT by hand but not with the cable. I put in new carpet and underlay a few years ago and I think it is too thick. Ill address that so I can get more pull on the cable with the gas pedal.

Yes the timing was set without the vacuum advance hooked up and the carb vacuum plugged off. I knew someone would ask me that as it can be a common mistake people make.

It is full vacuum to the distributor all the time which is the way this carb is designed.

My points and condenser were new in 2019 and I didn’t put many miles on it since then. I typically replace those every 2 or three years. Roughly 10,000 miles. I check dwell annually.

[MC1of80]

Aaron, at no time should you have constant vacuum going to the distributor. 

If that's how you run it, the engine is constantly running too far advanced. 

All vacuum advance distributors should be to PORTED vacuum. Otherwise just disconnect and plug the vacuum line and power time the car and leave it alone. You will have less timing than if you run constant vacuum to the distributor. 

Also, silly question? Did you adjust the valves or have the spark plugs wires off and maybe 5 and 7 crossed? The popping out of the carb is not normal or good. Either 5 and 7 are crossed or possibly a cam lobe is rounding out. Hopefully 5 and 7 are crossed. 

 

[Canuck]

6 minutes ago, MC1of80 said:

Aaron, at no time should you have constant vacuum going to the distributor. 

If that's how you run it, the engine is constantly running too far advanced. 

All vacuum advance distributors should be to PORTED vacuum. Otherwise just disconnect and plug the vacuum line and power time the car and leave it alone. You will have less timing than if you run constant vacuum to the distributor. 

 

 

This car has been this way all the years I’ve owned it. With that said there was a TCS solenoid when new but don’t know how that affected the vacuum advance. The TCS was gone before I got the car. There is no ported vacuum on this carb that I know of.

[Canuck]

My 70 doesn’t have a typical ported vacuum on the lower right front of the carb like my 71 has.

there was a period of time I had the vacuum advance plugged in the passenger side port on the carb and I plugged the air cleaner on the top front one. Not sure if that’s better or not.

 

[MC1of80]

Still needs ported vacuum. Not direct. With the carb rebuilt it probably works much better. The issue may have not been as noticable with the worn carb. 

5 and 7 plug wires in correct locations?