My 1978 Dodge Monaco 4 door sedan.

[Gary P]

Thanks Hawkster.

This mornings findings are below in this video I made.

I got it idling, not much else. Please watch…

 

[Don Frelier]

The vacuum pull off should have an imported vacuum source connected. Otherwise it will run really rich until the choke spring warms up.

Idle mixture adjustment should be done with the engine at operating temperature with the air cleaner in place.

Get the timing set run it a little fast if you need to to warm it up then set idle speed and finally mixture.
If everything is happy the idle speed will go up so slow it down and recheck. It's an iterative process.



Again take your time...
Sorry didn't see the video at first.

Plug the larger line that's causing the vacuum leak and remove whatever that thing is over the carb.

 

[Gary P]

The vacuum pull off should have an imported vacuum source connected. Otherwise it will run really rich until the choke spring warms up.

Idle mixture adjustment should be done with the engine at operating temperature with the air cleaner in place.

Get the timing set run it a little fast if you need to to warm it up then set idle speed and finally mixture.
If everything is happy the idle speed will go up so slow it down and recheck. It's an iterative process.



Again take your time...
Sorry didn't see the video at first.

Plug the larger line that's causing the vacuum leak and remove whatever that thing is over the carb.

Vacuum pull-off - I don’t know what that is or means.

Imported vacuum source - no idea what that means either.

I’m sorry, none of this terminology is familiar to me.
Remember, you’re dealing with a noob!!!!

 

[Gary P]

Also what is this? Does the vacuum it creates, shift the trans?

 

[64fury74charger]

View attachment 1314276

Also what is this? Does the vacuum it creates, shift the trans?

That looks like the diverter valve from the air pump for smog.

 

[Gary P]

That looks like the diverter valve from the air pump for smog.

Can this be plugged, you think?

 

[mpgmike]

Yes. The round thing you're pointing to is a check valve that allows fresh air to get pumped into the exhaust (for emissions reasons) without hot exhaust back feeding and burning out the pump/diverter valve.

 

[Gary P]

Yes. The round thing you're pointing to is a check valve that allows fresh air to get pumped into the exhaust (for emissions reasons) without hot exhaust back feeding and burning out the pump/diverter valve.

Thank you so much Mike, I’ll go ahead and plug that.

 

[Don Frelier]

Vacuum pull-off - I don’t know what that is or means.

Imported vacuum source - no idea what that means either.

I’m sorry, none of this terminology is familiar to me.
Remember, you’re dealing with a noob!!!!

Vacuum pull off is the space ship looking metal thing on the passenger side towards the top.

Sorry I meant unported meaning vacuum all the time. I think spell check messed that one up.

 

[Nxcoupe]

View attachment 1314276

Also what is this? Does the vacuum it creates, shift the trans?

No, that is the thermactor piping. That is a one way check valve. Just leave it be.
The thing just above the idle set screw you keep calling a thingamajig, is actually called a choke vacuum pull off. Please call it that. Part of working on this stuff is learning the terminology.
Again, there are 2 types of vacuum ports on the carb PORTED and MANIFOLD vacuum.
Again, ported vacuum increases the vacuum as as the throttle is opened and rpm increases.
The manifold vacuum will have vacuum at idle, but as you increase rpm, the vacuum at that port will decrease, it will go to 0 at wide open throttle.
Please put your finger over the various nipples on the carb baseplate and see which ones are manifold and which are ported.
Focus.
Yes, you have found the idle mixture screws and the idle speed screw.

 

[Gary P]

Took the cap off the top so it’s drawing more air. Won’t idle.

On full choke it idles and revs smooth all the way up, but off choke it won’t idle.

Timing - I’m sorry but that is still something I neither know how to do and also think at this stage is futile as it’s in the sweet spot already clearly as it idles and revs hard and well. I can’t see what difference a timing light is going to make. Maybe someone could explain that and also again how to do it.

Sorry that I am frustrating some of you.

Oh I turned the idle and mixture screws right in, and nothing changed. Didn’t back them out. It continued idling on full choke.

 

[Kern Dog]

Idling on a full choke seems to indicate a massive vacuum leak.
Is there a 3/8" vacuum nipple OPEN at the back of the carburetor near the bottom? What feeds the power brakes?

 

[Don Frelier]

Idling on a full choke seems to indicate a massive vacuum leak.
Is there a 3/8" vacuum nipple OPEN at the back of the carburetor near the bottom? What feeds the power brakes?

and pcv valve?

 

[Nxcoupe]

You don't adjust idle mixture or idle speed with the choke on. Fine, don't set your timing. You're not making it easy on us to help you. There are literally 100s of videos on you tube about setting initial timing.
If it runs fine, why are you still needing help?

 

[Kern Dog]

The timing light lead wire needs to be attached to the #1 spark plug wire. It will light up as that spark plug wire fires. Point that at the harmonic balancer and look for a horizontal groove, like so:

That groove will be visible when the timing light flashes. The goal is to twist the distributor to get that line to point to the timing tab on the engine...the one with the numbers on it. For a stock 318, you should aim for 5-8 degrees BEFORE top dead center.

 

[Gary P]

Idling on a full choke seems to indicate a massive vacuum leak.
Is there a 3/8" vacuum nipple OPEN at the back of the carburetor near the bottom? What feeds the power brakes?

Hi Kern,

There is a 3/8" nipple on the back of the carb, it goes to the breather on top of the driver side valve cover.
There is a nipple on the intake manifold, I think 3/8" too, which goes to the power brake booster, here...

The timing light lead wire needs to be attached to the #1 spark plug wire. It will light up as that spark plug wire fires. Point that at the harmonic balancer and look for a horizontal groove, like so:

View attachment 1314330

That groove will be visible when the timing light flashes. The goal is to twist the distributor to get that line to point to the timing tab on the engine...the one with the numbers on it. For a stock 318, you should aim for 5-8 degrees BEFORE top dead center.

This is exactly what I needed to know. I was on the right path too Kern, but you confirmed my grey area thanks man! So it was in that ballpark. Any more degrees =/- and it falls on its face. Let's now assume initial timing is now set. Still doesn't idle but does rev strong and smooth. My confusion at this point is to when I screwed the mixture screws all the way in, nothing happened!

 

[Nxcoupe]

Hi Kern,

There is a 3/8" nipple on the back of the carb, it goes to the breather on top of the driver side valve cover.
There is a nipple on the intake manifold, I think 3/8" too, which goes to the power brake booster, here...
View attachment 1314329


This is exactly what I needed to know. I was on the right path too Kern, but you confirmed my grey area thanks man! So it was in that ballpark. Any more degrees =/- and it falls on its face. Let's now assume initial timing is now set. Still doesn't idle but does rev strong and smooth. My confusion at this point is to when I screwed the mixture screws all the way in, nothing happened!

I addressed the fact of your idle mixture doing nothing, please read my previous post. You have a vacuum leak. The hose you have going to the valve cover breather isn't supposed to go there. It is supposed to go from the carb to the PCV valve in the other cover. There's your vacuum leak and your crappy running.

 

[Gary P]

You don't adjust idle mixture or idle speed with the choke on. Fine, don't set your timing. You're not making it easy on us to help you. There are literally 100s of videos on you tube about setting initial timing.
If it runs fine, why are you still needing help?

Ah, I apologize that all this has left you frustrated with me. I sure didn't mean that to be a thing. I guess it's hard for me to convey and be descriptive over a forum and I most certainly didn't ignore or diminish any of the priceless information your good self has added to this thread - to which I thank you.

I think for an engine newbie, there's a question, an answer, and for me certainly, about another ten questions as to why the initial answer is a thing!

So sorry about the frustrations I've caused here. I salute your knowledge and hope one day I can pass it on to another person completely overwhelmed like I am.

 

[Kern Dog]

I have been where you are Gary.....A problem exists and sometimes someone responds with the cure but somehow it gets missed.
For example:
10 years or so ago, I was dealing with some detonation problems that had me really frustrated. I posted about it on several forums and got a variety of responses. I glossed over some of them for some reason but after some time had passed, I looked back at those threads that I started and saw that the answers were there.....I just didn't see them.
Here is what I see. It may be wrong but it is what makes sense to me:
The PCV valve on the drivers side valve cover has a 3/8" rubber hose on it.....that needs to be connected to a fitting on the base of the carburetor. This is a full time vacuum source known as Manifold vacuum.
The 3/8" leading to the brake booster needs to be connected to another Manifold vacuum source. I see that it is connected to a fitting that is threaded into the intake manifold between the distributor and carburetor.
So far, so good.
At the front of the carburetor BELOW the steel fuel line is a smaller rubber hose that you have looped over to the passenger side. Try removing that hose and just plug both fittings. You can use a 2" section of hose with a bolt stuck in the end.

 

[Gary P]

I have been where you are Gary.....A problem exists and sometimes someone responds with the cure but somehow it gets missed.
For example:
10 years or so ago, I was dealing with some detonation problems that had me really frustrated. I posted about it on several forums and got a variety of responses. I glossed over some of them for some reason but after some time had passed, I looked back at those threads that I started and saw that the answers were there.....I just didn't see them.
Here is what I see. It may be wrong but it is what makes sense to me:
The PCV valve on the drivers side valve cover has a 3/8" rubber hose on it.....that needs to be connected to a fitting on the base of the carburetor. This is a full time vacuum source known as Manifold vacuum.
The 3/8" leading to the brake booster needs to be connected to another Manifold vacuum source. I see that it is connected to a fitting that is threaded into the intake manifold between the distributor and carburetor.
So far, so good.
At the front of the carburetor BELOW the steel fuel line is a smaller rubber hose that you have looped over to the passenger side. Try removing that hose and just plug both fittings. You can use a 2" section of hose with a bolt stuck in the end.

Thank you!

I totally mis-identified the PCV valve as a breather! Sorry about that. So, I checked that hose, it's not split or cracked but I'll replace it anyway, so I have Manifold Vacuum.
Yes, you're right in your observation - the brake booster has manifold vacuum too, from a fitting in the intake manifold.
I'll plug up both fittings in the front and side of the carb as you say. (I just joined them together with the same piece of hose as a quick plug)

Sorry about all this.