Won’t idle after new muffler

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standup303

standup303

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Just did a few odds and ends to the dart. New muffler, spark plugs, plug wires, fuel filter, air cleaner, adjusted valve lash, changed oil, added some coolant.

Ran fine yesterday, zero issue. Go to take a drive tonight and it will barely idle then dies. Then gas leaks out from the bottom of the carb onto the intake manifold.

Going to start re-tuning the carb and see what that does but figured I would post up and hopefully get some tips. Thanks in advance for any help!

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Tighten all of the fasteners up on the carburetor. The bolts that hold it on the manifold and all of the screws that hold the carburetor together. They are notorious for working loose as the gaskets shrink over time.
 
Just don't tighten them too much, itll distort the body potentially crack the ears off.

Probably just coincidental that your carb needs to be re gasketed , float inspected needle & seat replaced AKA rebuilt.

If it were the muffler ...it would be one of two symptoms, from one of two causes. First one... it would idle lower if the muffler had no back pressure and was put in place where a stock Style Muffler was used before....or B the other way around and the idle goes up to 1200rpm. Lol

Vac leak...and "Do I have a vacuum leak" should be the title of this thread.

Jmo
 
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Common for debris to clog the needle/seat after disturbing the fuel filter. Bogging down.
Whenever it happened to me,
I used to start the engine then Rev the throttle while snuffing the air with my other hand, choking until it almost stalls a few times, really working the throttle.
Almost always sucked all the crap out, and idled nicely afterwards.
 
Give the carb a coupla sharp raps just behind where fuel line goes in.
Not hard, you're trying to jiggle the needle/seat to free debris .
If it still leaks fuel, diss-assembly may be required .
 
Has nothing to do with the new muffler. Got our attention though.
 
Midas put a new muffler on a p/u truck, it started, ran, coughed, died, cranked, wouldn't start.
They pulled timing cover to replace jumped chain, messed with it a coupla days. It'd start in morn , stall, no restart.
Frustrated customer called us, we got truck, checked it out, new muffler plugged shut .
 
A friend of mine had a Volare Station wagon with a similar problem. I took a look at it, and somehow the carb had gotten loose. You could hold the top of the carb and wiggle it around while the base stayed solidly fastened to the manifold. I took the carb off, and the somehow the screws that held the carb's body to the base plate had all worked loose. I tightened them up and it ran fine. It was leaking fuel and did not want to idle due to vacuum leak.
 
inertia said:
Midas put a new muffler on a p/u truck, it started, ran, coughed, died, cranked, wouldn't start.
They pulled timing cover to replace jumped chain, messed with it a coupla days. It'd start in morn , stall, no restart.
Frustrated customer called us, we got truck, checked it out, new muffler plugged shut .
Click to expand...
No exhaust pressure from the tail pipe would be the first clue. Like a plugged converter. Or a tail pipe with a potato jammed in the end. LOL
 
inertia said:
Midas put a new muffler on a p/u truck, it started, ran, coughed, died, cranked, wouldn't start.
They pulled timing cover to replace jumped chain, messed with it a coupla days. It'd start in morn , stall, no restart.
Frustrated customer called us, we got truck, checked it out, new muffler plugged shut .
Click to expand...
Makes you wonder about some shops.
 
inertia said:
It took us a bit to figure it out, - new parts eh ? lol
Huge cough return outta carb, gave it away .
Click to expand...
Sometimes we spend a lot of time looking for other things since we "Know" it can't be that "New" part. Then later we find that the new part was defective.
 
slantsixdan said:
Unrelated, but why's your vacuum advance nipple plugged off instead of connected to the distributor?
Click to expand...
When I go to a cruise night I am surprised at how many cars of all brands I see like that
 
It'll be identified as the "OSAC" port in many carburetor manuals, because starting in '73 many cars had an OSAC valve (Orifice Spark Advance Control) to try to squeak the cars past new-vehicle emissions type-approval tests so they could be legally offered for first sale. In '73 the valve was on the passenger side of the firewall; starting in '74 it was on the side of the air cleaner housing. If your car has one, pretend it doesn't exist—run the hose directly from the carburetor to the distributor. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download; yours is a Holley 1945.
 
Thanks all. Cranked the car up and hammered on the throttle pretty good for about a minute. Took it on a 15 minute drive right after, no more idle or carb leak issue. Hopefully it stays this way.

Thank you for pointing out the missing hose, I will install one this weekend.
 
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