Slant six 1920 stall

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Dogdish95

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Hello,
I have a 225 slant in a 1969 Plymouth Valiant four door. I am having an issue where when I have the car in gear it has no issue Idling then after about a minute it sputters and stalls killing the engine. Upon watching this the fuel evaporates and floods the vent and boils in the throat of the carburetor. My exhaust butterfly valve moves freely. I have rebuilt the carburetor using a kit replaced all rubber lines and checked for vaccine leaks. Chokes opens and closes when it should. I have not checked the valve lash or points. Car is manual brakes and steering auto transmission. The fuel lines are not hot and the pump seems to be good filling the lines and providing a good shot of fuel when driving. Only happens when the gas is not pressed.
 
Hello,
I have a 225 slant in a 1969 Plymouth Valiant four door. I am having an issue where when I have the car in gear it has no issue Idling then after about a minute it sputters and stalls killing the engine. Upon watching this the fuel evaporates and floods the vent and boils in the throat of the carburetor. My exhaust butterfly valve moves freely. I have rebuilt the carburetor using a kit replaced all rubber lines and checked for vaccine leaks. Chokes opens and closes when it should. I have not checked the valve lash or points. Car is manual brakes and steering auto transmission. The fuel lines are not hot and the pump seems to be good filling the lines and providing a good shot of fuel when driving. Only happens when the gas is not pressed.
Issue was needle and seat installed incorrectly
 
Closest thread to my problem so thought Id tail on, sorry.
Ive been ironing out problems on the 63 dart 225. I installed a Super Six setup with a holley 2280 Id rebuilt a few years ago.
Got it where it is running very nicely but cant seem to get it to go to idle when stopped at stop signs or lights or stopping quickly even when warmed up well.
Ive raised idle up a half turn and now its up to 1500rpm or so and still happens, high enough that when I put it into D, it wants to take off.
Any thoughts on this? Check the solutions up above?
Thanks.
 
Next on the list, gotta get back to town and get my f'n back healthy enough to lean over the fender again.
:^?
 
Issue was needle and seat installed incorrectly
which needle are you referring to? I have the EXACT issue. I have replaced the carb twice and it still stalls out. I am a total noob when working on cars so explain like i am five please.
 
1920%20float%20system.jpg
 
Closest thread to my problem so thought Id tail on, sorry.
Ive been ironing out problems on the 63 dart 225. I installed a Super Six setup with a holley 2280 Id rebuilt a few years ago.
Got it where it is running very nicely but cant seem to get it to go to idle when stopped at stop signs or lights or stopping quickly even when warmed up well.
Ive raised idle up a half turn and now its up to 1500rpm or so and still happens, high enough that when I put it into D, it wants to take off.
Any thoughts on this? Check the solutions up above?
Thanks.
> make sure your fuel tank is venting.
>If you have a PCV system, make sure that it is fully functional.
>If you don't have a PCV system, but your carb has the port, then it was designed to run one.... so you will need to plumb one in. If you don't, the carb will NEVER run right.
>If you have a brake booster, pinch the line off for testing.
>Also for testing; Disconnect the Vacuum line to the Distributor and Plug the carb port.
>Reset your float level to the factory spec. I recommend you pressure test yours to 4.5 psi; it must hold at 4.5 for at least a minute. Longer is better.
>Retard your timing to between TDC and 5* BTDC.
>Put the mixture screw(s) to "in the center of their range" usually about 2T from lightly seated.
>Start it up and reset the idle to 500 in gear, which should be no more than 600 in Neutral. If it won't idle down there,see note-1, then warm it up again, and see how it idles.
<If it runs good, try some different mixture screw settings and yur done.
<If it runs good for a while then stalls; this will be a fuel-delivery problem. You will have to figure out if it is flooding or if it is running out of fuel; see note-2

Note-1
If it won't idle at 500 in gear; you will have to figure out , firstly if the TC is seized.If the TC is OK, then; if the engine has; a fuel problem, an air problem, an ignition problem, or a mechanical problem.
So the first thing I would do is; warm it up, then reset the valve lash to minimum .013 on the intakes, maximum .023 on the exhausts. But make sure you use narrow feeler gauges no wider than the valve stems. While the covers are off look for bad valve springs and bent pushrods.
note-2
First check the venting; if good, then do a fuel-delivery test. If good then move to the float-valve and the low-speed circuit.
note-3
If has an idle misfire, and has points, dress and clean the points. If it still misfires, replace the condenser. If it still misfires and twiddling the mixture screw does not improve it, then go look for vacuum leaks. If none found and still misses, then do a compression test. If compression is even on final, and every compression cycle is strong from the get-go, then replace the plugs. If still misses, replace the gas. If still misses do a leakdown test. If that shows good then check for bad valve springs. If still misses; IDK so I'm done.
 
got back from Methow and ran through the carb, adjusted the floats to 9/32 and cleaned the bowl out as there was a bit of crap there. Took out the idle screws and blew out the idle circuits and others. It runs better now but warm idle in Park is 1300rpm in gear it drops to 500rpm. Driving and coming to a stop it seems like it still wants to die.
Replaced the funky PCV hose as it was collapsing when running.
Trying to figure out how to plug off one of the carb vacuums ports as it is very small.
It has no PS so no booster. I have tried to spray fluid around the carb base and the intake but dont seem to find any vacuum leaks there.
Fuel tank has no vent in the system.
So when you say "Reset your float level to the factory spec. I recommend you pressure test yours to 4.5 psi; it must hold at 4.5 for at least a minute. Longer is better." Are you sayingReset float to factory. Then,
Pressure test fuel delivery @ 4.5 psi or some how pressure test the float? Its a bit ambiguous to me. Can you break that down please? Also "TC"?
It is an electronic distributor so no points.

Cheers.
 
got back from Methow and ran through the carb, adjusted the floats to 9/32 and cleaned the bowl out as there was a bit of crap there. Took out the idle screws and blew out the idle circuits and others. It runs better now but warm idle in Park is 1300rpm in gear it drops to 500rpm. Driving and coming to a stop it seems like it still wants to die.
Replaced the funky PCV hose as it was collapsing when running.
Trying to figure out how to plug off one of the carb vacuums ports as it is very small.
It has no PS so no booster. I have tried to spray fluid around the carb base and the intake but dont seem to find any vacuum leaks there.
Fuel tank has no vent in the system.
So when you say "Reset your float level to the factory spec. I recommend you pressure test yours to 4.5 psi; it must hold at 4.5 for at least a minute. Longer is better." Are you sayingReset float to factory. Then,
Pressure test fuel delivery @ 4.5 psi or some how pressure test the float? Its a bit ambiguous to me. Can you break that down please? Also "TC"?
It is an electronic distributor so no points.

Cheers.
Fuel tank vent is small tube that runs a torturous path from the top of the filler neck & drops thru' the the trunk floor seal next to it. Common for bugs/spiders/rusty crud to block it up. TC=Torque converter, if the stator is seized. Verify correct running fuel psi, AND apply 4.5psi to carb inlet & check for bleed-down, indicating leaky needle/seat/body/gasket. Small 'lectric pump works, then kill it & watch, You kin pinch the hose to keep pump check valve out of the variables column.
 
Last edited:
Thanks, K6.
So I have no pressure gauge nor pump to generate pressure other than my small air compressor. Do you have suggestions on the tools and how to proceed?
This is new to me.
 
You can blow about 2.5 psi so if the carb is full, You should not be able to blow into the fuel line (yuck). Some mighty-vacs have a positive pressure port. A jiggler style electric pump usually puts out less than 4 psi, And they are super cheap online. Great on a slant.
 
got back from Methow and ran through the carb, adjusted the floats to 9/32 and cleaned the bowl out as there was a bit of crap there. Took out the idle screws and blew out the idle circuits and others. It runs better now but warm idle in Park is 1300rpm in gear it drops to 500rpm. Driving and coming to a stop it seems like it still wants to die.
Replaced the funky PCV hose as it was collapsing when running.
Trying to figure out how to plug off one of the carb vacuums ports as it is very small.
It has no PS so no booster. I have tried to spray fluid around the carb base and the intake but dont seem to find any vacuum leaks there.
Fuel tank has no vent in the system.
So when you say "Reset your float level to the factory spec. I recommend you pressure test yours to 4.5 psi; it must hold at 4.5 for at least a minute. Longer is better." Are you sayingReset float to factory. Then,
Pressure test fuel delivery @ 4.5 psi or some how pressure test the float? Its a bit ambiguous to me. Can you break that down please? Also "TC"?
It is an electronic distributor so no points.

Cheers.

That's a huge RPM jump from park to drive. Where do you have your initial timing set?
 
Thought it was around 5btdc but I have been doing so much messing around trying to iron out all the other odd crap, Ill have to check it again tomorrow.
Surely hate the thought a a bad torque converter, how do you even go about checking that? Is there something else that might mimic that overloading of it?
Really hate the thought of tearing into the carb again and doing the pressure testing. Just had it torn apart yesterday. But seem to be getting some good progress now. Frigging cars!
Thanks for the suggestions.
 
I also found my paperwork for the cam I got from Oregon Cam #819, intake and exhaust clearance is listed at .012.
Found that I do have a fuel pressure gauge on my OTC along with vacuum gauge. Ill check timing and fuel pressure tomorrow. Been crappy rainy here.
 
Forgot to add that when I replaced my plugs they were less than 1k miles and seemed pretty fuel fouled. There is also some slight dieseling when shutting off.
 
Latest update,
I finally got a chance to get back on the Dart this week.
A couple of weeks ago I installed an electric choke so that part is taken care of now.
I tried to check fuel pressure with my pressure/vacuum gauge. Tee'd into the fuel line with the tee supplied with my gauge but it is a like 1/8" tee and my line is bigger. Tried to clamp it shut be it leaked and the plastic tee broke.
I also tried to get the idle down to 600-700 but it still will run ok there then drops dead. It seems to want to idle 1-1.2k rpm and seems to be ok but going lower results it it dying.
I drove it around yesterday and when running does fine but coming to a stop it still wants to die. I did notice something funny to me, if I hit the brakes hard when coming to a stop the engine seems to want to die also. I know a vacuum booster leak would likely cause this but the car is all manual so it seems weird to me.
It is idling roughly also, tried adjusting idle control to no avail.
I also sprayed some starter fluid at the throttle bushing area and it would speed up leading me to believe the holley is worn.
I am so tired of fighting this because it hurts my body too much, Im ready to push it into the lake, anyone have a 2 barrel carb in the pacific northwest they would like to rent so I can check this out or would be willing to lend a hand?
 
I also found my paperwork for the cam I got from Oregon Cam #819, intake and exhaust clearance is listed at .012.
Found that I do have a fuel pressure gauge on my OTC along with vacuum gauge. Ill check timing and fuel pressure tomorrow. Been crappy rainy here.

For testing purposes,
So the first thing I would do is; warm it up, then reset the valve lash to minimum .013 on the intakes, maximum .023 on the exhausts. But make sure you use narrow feeler gauges no wider than the valve stems. While the covers are off look for bad valve springs and bent pushrods.
until you do this I ain't saying nuttin' more.
 
Ok maybe this;
after the lash is reset;
you must do a compression test, and do it correctly by, at WOT, cranking until you get two consecutive same or similar numbers on every cylinder. The results must be even or close to even, between all cylinders. I like numbers over 140, but if the cam is not stock, the numbers may not be meaningful, other than they must be even and reasonably high, which to me would be over 125.
I would do a LeakDown test to prove the valves are sealing; But you the compression test will do for now.
Now;
if you have a carb that looks like the one in post #7;
take the carb off, make sure the choke is off, then flip it upside down. Close the throttle completely with the speed screw. Then open it until the transfer slot is about square. If your cam is not stock, you can open it a tad further, say to a lil taller than wide. Flip it rightside up. Reset the mixture screw to 1.5 turns from lightly seated. Block ALL vacuum ports except the PCV and make sure that port is open.
After this, DO NOT Touch the speed screw again, until I tell you to.
Reinstall the carb, making sure the gasket is the correct one for both the intake and the carb. Pour some fuel, about 40/50cc into the float bowl thru the bowl-vent. Remove, or at least loosen, the gas cap.
Loosen the distributor hold down just enough so that you can rotate the distributor with some difficulty. If you still have points, set them to the factory spec (I forget what it was, guessing .019 or so).
Make sure the PCV system is working, including that the hose is rated for PCV and not collapsing under vacuum when it warms up.
Do not reconnect the Vacuum advance.
Ok
now, in a minute,
you are gonna start the engine and warm it up. If the intake is not sucking air somewhere, and if the valves are sealing, and if the ignition timing is close, and if the float level is correct and remains correct; then the engine will start right up and after a short warm up, it should idle in the ballpark.
If it doesn't;
and if the idlespeed is too slow, you will advance the timing until the idle speed is in the ballpark. If it will not speed up into the range of 550 to 600 in Neutral/Park; either the float level is very high and the carb is flooding, or the cam-timing is suspect.but
if the idlespeed is too high;

by only a couple of hundred rpm, you will retard the timing until the rpm settles down. But if the rpm us well over 800 rpm; the intake IS sucking air, or the carb is sending unauthorized air/fuel into the intake, or the cam-timing is suspect.
If the engine is hard to start after the fuel level is stabilized AND If you didn't do a LD test earlier, now is the time to do it...... because; If the exhaust valves are not sealing during cranking, the falling pistons on the intake stroke will suck air from the exhaust system, instead of air from the plenum. This air in the exhaust has no fuel in it so of course it will be hard to start.
It could happen that the valves are sealing but at the wrong time, so once again, that would point to wrong cam-timing.
As for ignition timing; the engine is not particularly fussy for timing during cranking, as long as it's not retarded or crazy-advanced. But the further it is from ideal, the more throttle it's gonna take to keep it running after it begins to fire. Retard is worse. But remember, I told you not to mess with the speed screw until I tell you to. and we ain't that far yet.

Ok, now you know what to expect and what to do if it don't do what you expect,lol;
so crank it up and fix the idle.Until you get the idle fixed don't bother putting it into gear and don't even think about driving it.
Your target rpm for neutral/park should be from 500/550 for a stock cam, to 700/750 for a big street-cam.

PS; I don't have specs on your cam. If you do, please post them up, so I can get an idea of where to go from here.
 
Wanting to stall under braking sounds like fuel level in the carb is too high. So check float level, any binding, etc & condition of n/s. High fuel pressure will also raise fuel level.
 
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