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major lagging on hot restart and sudden cough and sputter
https://slantsix.org/forum/viewtopic.php?t=46190		 Page 1 of 1
Author:  Chetterhead [ Thu Sep 01, 2011 2:53 pm ]
Post subject:  major lagging on hot restart and sudden cough and sputter
I've been having some problems lately on hot restart. typically, if it's been running solid for a bit (half hour of freeway or sustained 40+mph for back and forth surface), it restarts fine, but is going to barely run for several minutes. I let it sit and run for three or four minutes (on hot restart) and then I expect a good block or two of babying the throttle at low speeds and a lot of sputtering, then it kind of shakes it off and runs fine.

in the morning or on first start of the day, it gets around ten minutes of warm up, but it always takes it about a block or so to clear it's throat and get it to where I can give it gas and it'll respond normally (normal for Chet).
during warm up, it starts strong and you can rev it up no problem. the only issue there is if you really punch it quickly, it'll cut out, but comes right back.
I've done Dan's fuel line mod, about a month ago.
my carb has the most ridiculous filter on it. something like four inches. had to look everywhere for a new one in town.
I know the carb needs work because there are plugged in/outlets and the link to the dashpot from the clutch arm was hanging loose everywhere from cold to hot. no tension at any stage.

just now I went out for the first time today, gave it ten minutes of warm up, it backed out and went two blocks with it's normal lag in the beginning, then while turning (and looking at another Dart) it almost cut completely out. it was as if it was out of gas, but it can't be. it actually seems to be getting great mileage. so I brought it back home, which was about a half mile trip and it drove ok up around 30mph, but when it came to slowing down or getting going from a stop, it sputtered.

so where's my gas??
Author:  wjajr [ Thu Sep 01, 2011 4:39 pm ]
Post subject: 
I would say it is time for a carburetor rebuild. But before you do, try to make a few adjustments after reading this[url=http://www.slantsix.org/forum/viewtopic.php?t=33102] page[/url].

Pay close attention to automatic choke, and check the choke pull-off ( little rubber diaphragm with a bent rod sticking out of it) by using a small rubber vacuum hose hooked to it. Push in on bent rod, than place finger over vacuum tap and see if diaphragm holds a vacuum and keep rod retracted. If it dose not, you need a new diaphram

As for the big filter, perhaps previous owner had problems with a lot of crud in gas tank migrating to carburetor constantly plugging up the works . Change it before any adjustments, you don’t need to match it, just get a metal cased fuel filter, not plastic or glass.

Often some of the vacuum taps on a carburetor will be plugged off because it is a carburetor from a different year car that someone has adapted, this is common. What you have to do is make sure what your car needs to run is connected to the proper vacuum source.

Most important is the vacuum advance pod located on side of distributor has to be connected to “ported Vacuumâ€￾. This is the only tap on carburetor that has no vacuum at idle, and supplies vacuum once engine is off idle. It is generally located just above elevation of throttle plate when closed. This is important because the engine dose not want any timing advance at idle other than its base setting.

If carburetor is working properly one should not need to let engine warm up more than 5 to 10 seconds from a cold (overnight) start, and it should restart easily and run smoothly the rest of the day.

I suspect that you may have a vacuum leak somewhere, makes for poor idle. Accelerator pump is not giving a good shot of fuel, causing stumbling when accelerating. Fuel is boiling after stopping causing hard starting, a heat shield and proper gaskets will fix it, and idle mixture screw is out of adjustment.

Also you should check the valve lash if you haven’t done so, as out of adjustment lash will cause poor drivability as well.

All these problems can be easily fixed once you identify them.

Do you have a Factory Service Manual for your car?


Let us know what you discover.
Author:  Chetterhead [ Fri Sep 02, 2011 10:18 am ]
Post subject: 
Image

Image

this is my carb. the dashpot for the choke works. the vacuum closes and opens it, but the U link never has tension on it at any point from cold to hot. the rod connected to the other side moves fine during warm up.
the throttle modulator is gone. pretty sure that's supposed to be there.
you can see fast weld on it behind the idle screws. I didn't do it, so I don't know what it's covering.
I really need/want to get a heat shield and new gaskets.
the port next to the one going the dashpot is capped.

the numbers stamped into it are:

4712
3069
no letters

I want to get a rebuild kit, so can anyone tell me which 1920 I have and point me in the right direction?

the thing I don't get is why it suddenly nearly died on me. it hasn't done that before.

on a side note, I put a pint of marvel mystery oil in the crankcase and a bottle of Lucas fuel system cleaner in the gas. I'm not the kind of person to dump in additives and expect miracles (or any positive results), but the marvel came highly recommended and Lucas I already trust.
Author:  Aggressive Ted [ Fri Sep 02, 2011 11:56 am ]
Post subject: 
What RPM do you have the idle set at? It may be too low causing the stall.

It would be interesting to pop the 4 screws loose holding the bowl and catching all the fluids to see what is floating around in there.....
I use a plastic Folgers container cut down to slide under the bowl. That way the gas doesn't drip down all over the engine. Then I run it through a funnel with a filter and put it back in the tank.

If there is a lot debris, then the filter isn't doing you much good.

On warm ups about 15 seconds and I am gone......
Author:  Chetterhead [ Fri Sep 02, 2011 12:05 pm ]
Post subject: 
coffee can! good idea!

I'm gonna go do exactly that.

thanks! I'll let you know what does or doesn't come out
Author:  Aggressive Ted [ Fri Sep 02, 2011 12:07 pm ]
Post subject: 
I use a the red Folger's plastic container....it is easy to cut and fit.
Author:  Chetterhead [ Fri Sep 02, 2011 1:15 pm ]
Post subject: 
i had to use the lid of a plastic storage box because there's maybe an inch of clearance, but:

Image

the gas had some flecks of grit in it. I'm wondering if the float can get fuel soaked and sink?
Author:  SlantSixDan [ Fri Sep 02, 2011 1:21 pm ]
Post subject: 
Bet the float is heavy and the carb needs a go-through. Put in a new one, Walker #100-14 or NAPA Echlin 2-471. Get a good quality carb kit from www.daytonaparts.com but be advised it (like almost all others) won't come with the correct float gauge and you'll have to improvise. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Tune-up parts and technique suggestions in this thread.
Author:  Jeb [ Fri Sep 02, 2011 4:50 pm ]
Post subject: 
When you get the carb sorted out, I would recommend getting another air cleaner. Those itty bitty ones like you have on there now get clogged up with dirt rapidly, and the flow rate is pretty bad.
Author:  Chetterhead [ Fri Sep 16, 2011 10:20 am ]
Post subject: 
I hate that stupid air filter...
I was trying to replace just the filter and the guy pointed me towards sear's lawn and garden.
I found one randomly in pep boys' racing section.

My next move(s) would be to buy a carb rebuild kit and a new radiator.
I'll let you guys know what happens when I can actually afford that.
Author:  wjajr [ Fri Sep 16, 2011 1:35 pm ]
Post subject: 
For future air cleaner purchases, make it easy on your self, and write part number etc on inside of air cleaner cover. I have to do stuff like all the time.
Author:  Aggressive Ted [ Fri Sep 16, 2011 1:41 pm ]
Post subject: 
Why don't you grab a stock air filter assembly from the bone yard?
They are designed for better mileage than the one you are using.
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