New to me 78 NYB on its way but please Don't tell my wife

[73 T&C]

Had a eureka moment today... I’ve been searching for a possible vacuum leak for months.

Thought I found it when I replaced the vacuum line to the vacuum sensor on the Spark computer. Better but still there.

Went to check the bowl vent solenoid. It’s holding vacuum as much as you want. Then I checked the vacuum line from the solenoid to the carb. That line has a built in copper restrictor in the line just before the nipple on the carb. Turns out the line had carbonized and cracked right at the edge of the restrictor. It was a tiny crack and was held fairly closed in its position.

Removed the restrictor from the old line and put it into a new line.

Guess what... it was cracked enough to cause the idle to be rough and intermittently so. It was driving me crazy...

Guess what else I’m doing tomorrow. Changing all the vacuum lines on the top of the engine.

Tomorrow is shop day.

 

[73 T&C]

I'm sure you have probably checked it already, but it should be mentioned: Have you checked the pressure cap on the radiator? Is it working, and is it the correct cap (16 lbs, I think)? Sometimes its the really simple stuff that defeats us. . .

Defeat comes only if you give up! I’ll keep banging on it til I get it.

 

[commando1]

I'm not saying anything....

 

[73 T&C]

Bumper out and as good as before.... which is to say.... so so.

Checked the nos radiator cap for pressure... 16lbs bang on.

Checked fan clutch temp at thermo valve with IR thermometer after run....195 with radiator temp at 210. ( guage reading top of normal operating temp..... note to self with regard to reading). New Hayden 2747 fan clutch ordered... thanks Jeff!

Put guard on top hose just because.... because.

Working on vacuum lines now.

Posting while it cools down some.

A little crowbar and wood blocking. She popped right out on the right and back in on the left.

Head on view... light lines up again

3/4 view... no harm; no foul

Nifty hose protector that came with new hose.

 

[commando1]

That sleeve over the upper radiator hose is a good idea. It gets a lot chafing in the spot.

 

[73 T&C]

New low beams today. And took off the front plate and holder

 

[commando1]

Seriously...
We're down to showing pictures of new bulbs, now?
Slow news day.

 

[73 T&C]

Rainy day Sunday

 

[commando1]

Rainy day Sunday

The damn ditches and runoff ponds are overflowing. Jeezes.

 

[73 T&C]

Got a good Chew toy for us...

And would like some advice with a problem please.

Car is running almost perfect. Transition from cold to warm is now seamless with just the normal slightly lower power until temp starts to move off the stops. Warm up is usually complete in the first mile and a half enrichment cycle comes off followed by choke full off soon thereafter.

That’s where I need some advice as to what to check for an intermittent miss that ruins the whole experience.

While running off idle it pulls very well with no miss. As I pull to a stop for more than 3O seconds. It develops a miss.

Question is: why? And your recommendations as to solution would be appreciated. I have my own ideas but would like some contrasting/verifying opinions please....

 

[commando1]

As I pull to a stop for more than 3O seconds. It develops a miss.

Are you saying...
you come to a stop, and after idling at that stop for 30 seconds, it developes a miss?
IF so, this is an easy one.

 

[Ripinator]

Are you saying...
you come to a stop, and after idling at that stop for 30 seconds, it developes a miss?
IF so, this is an easy one.

Fouled plug?

 

[73 T&C]

Are you saying...
you come to a stop, and after idling at that stop for 30 seconds, it developes a miss?
IF so, this is an easy one.

Yes....

 

[73 T&C]

Fouled plug?

That’s what I’m thinking.

 

[commando1]

Yes....

In trying to remove the stumble, the idle circuit has become too rich. It's loading up.
You're gonna have to focus in more on those %$#@- metering rods.
Recheck for freedom of movement.
If I recall correctly, there's o-rings that need to seat probably.
Futz with going to one size larger or a weaker spring.

Thermoquad Repair Guide.

 

[73 T&C]

In trying to remove the stumble, the idle circuit has become too rich. It's loading up.
You're gonna have to focus in more on those %$#@- metering rods.
Recheck for freedom of movement.
If I recall correctly, there's o-rings that need to seat probably.
Futz with going to one size larger or a weaker spring.

Thermoquad Repair Guide.

Nope.... but interesting take.

Idle is set fairly lean at exactly 1-3/4 turns off the stops. No rich bog or delay on acceleration or with the secondaries.

Just changed air filter to boot... just to make sure the plug aren’t loading up. It was actually pretty bad. Shame on me.

BTW.... loved the link....

 

[73 T&C]

not sure this was leaking but, as a check valve, it’s done

New one ordered.

 

[cantflip]

Thermoquad Repair Guide.

 

[commando1]

New one ordered.

Where did you find it. I had trouble finding it when I needed one.

 

[Ripinator]

not sure this was leaking but, as a check valve, it’s done

View attachment 203037

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New one ordered.

Euueeeewww!