Motor is hard to start after warm up

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mullinax95

mullinax95

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My motor (273 with 500cfm Edlebrock carb) will crank good when it is cold but when I drive the car and let it set for 30 mins or more it will take a while before it will fire up again. It seems to have a hard time to get going after it finally cranks. I'm thinking that the carb is fluiding but not sure. I don't pat the throttle any before I crank it up because I'm thinking it is already got to much gas as is. I have mashed the gas pedal down just a little bit to let the motor get more air and it seems to help. The carb is mounted with a gasket between the intake. Do I need a heat divider or something? Thanks.
 
Next time, after shes warmed up, re-depress the gas to set the choke and tell us what happens.
This could be a clue.
 
rumblefish360 said:
Next time, after shes warmed up, re-depress the gas to set the choke and tell us what happens.
This could be a clue.
Click to expand...

I have the manual choke carb. Does that make a differnce or will it still work? I have to floor it and let it up and crank it right?
 
Sorry, I thought (Eh-hem, assumed) it was a eletric choke carb. Try to close the choke a tad and the start it up.
If it fails after a try or two, pump it with a little gas to feed it and try again.
It will probably start with the choke closed a little.
The idea being to speed up the air and get a better air fuel mix going.
To much cold air and the engine will not start.
 
Here's a few things to check:


Are you SURE it's flooding? Sometimes the fuel will evoparate from heat and/or the fuel bleeds back and has to re-prime the carb. Pull off the air cleaner and hit the throttle while looking directly down the barrels. If nothing sprays, your out of fuel. Have an assistant crank the engine, or you can jump the starter relay, and see if it pumps fuel while cranking. Start with a new fuel pump if this works and if there's no excessive heat happening.

Now if it's NOT starving for fuel, check spark. The coil and/or the ECU box are temperature sensitive. If either one is starting to go bad this is when it could happen. Also check to make sure the terminal plug on the ECU control box is firmly seated. I chased an intermittant no-spark condition for 2 days before I discovered a cracked terminal end in the plug that would spread when connected and cause NO CONTACT... THAT was a pain-in-the-***. If you have 12 volts at the coil and no spark, it's the coil. If improper voltage is present, check the ECU or the ignition ballast resistor. Fortunately Mopar distributors are pretty much bullet-proof. Rarely do the pick-up's go bad.

Don't forget the simple things too... Do you have a solid ground from the battery to the block and to the frame? Heat = Resistance.

Let us know where you end up as this will help someone else. And of course, if I missed something, someone else please drop your .o2.
 
Get yourself a compression gage and get a cylinder pressure reading. What was the exact buildup? Was the camshaft used degreed when it was installed?
 
mikesduster said:
it could be the timing??
Click to expand...

Boy-oh-boy I missed a simple one. I'm so used to working on junk that sometimes we forget the simple answers. #-o

Start with Mikes answer...;)
 
Well I drove the car to church this morning and it cranked fine as it always does when it is cold. After chruch (1hr 1/2 later) I got one of my buds to come out and give his thought on it. I told him the deal and I just got in didn't do anything but turn the switch and it fired up after about 4 seconds of turning over. He really didn't say much but it seemed fine to him. But now after driving it some more and taking note of how long the cars sits after warm up it only acts funny when it sits between 15 min to 30 mins. It seems that if it sits longer that a hour it will fire up better. I might need to add that when I come home and shut her down I can just tap the switch and it will fire up on the spot. I looked at the carb yesterday and in between the carb and intake there is a gasket, metal gasket and then another gasket. Like that is maybe some kind of heat shield. ???
 
Just for giggles, next time you have some time, before you get in and try to start it up, see how much gas is in the fuel bowls. Take the top off and look inside.
My old AVS leaks at the throttle plates and drains some. The first time I get in it after a day or 2 or a week or 3, I need to turn it over for about 10 - 15 seconds and then pump it a few times to get gas running through the carbs passage ways.

Let it be known that I have not really had the chance to finish tuning the carb or drive it around. It has no plates. But I did do some work to the car and does , everyonce in a while need to be moved around. You describe my car in your discription of your car.

Have you had a chance to close the choke slightly after it sits for a bit?
 
No the choke does not have a cable to it. I might need to install rod to hold the choke plate open matter of fact. The carb is brand new out the box so I believe it might need some adjustment... maybe not. I have adjusted the idle mixture but I don't think that would have anything to do with it. I turned them out 2 1/2 turns to achieve the highest RPM.
 
You know that sounds like some gas is seaping in somehow. That would expain it, Right after you stop and then start it thats not enough time for the gas to drip in. After a 1 hour or more the gas goes away and or the motor likes that little bit of gas cuase its getting cold. But after 15 mins its like flooded. Bet that it it, but I am a Holley guy so I would call Eddy tech and ask them. Could be your float is too high, but I would call them, think its a toll free #
 
dodge freak said:
You know that sounds like some gas is seaping in somehow. That would expain it, Right after you stop and then start it thats not enough time for the gas to drip in. After a 1 hour or more the gas goes away and or the motor likes that little bit of gas cuase its getting cold. But after 15 mins its like flooded. Bet that it it, but I am a Holley guy so I would call Eddy tech and ask them. Could be your float is too high, but I would call them, think its a toll free #
Click to expand...

I checked the online owners manual and checked the float level adjustment procedure and you have to take the air horn off, flip it over and insert a 7/16 drill bit in between the air horn and float and bend the float arm if it needs it. Then you check the float hang by flipping it back over and it should not I believe I would have to look again to make sure more than 1 1/4 " You are on the money far as I'm concerned. I can take the breather off and smell a fresh gas smell that is strong like I have hit the throttle once or twice. But my bull headed self thinks that it should be Ok since it hasn't been on the car long out of the box. I will check it when time allows. Time not enough it the day!
 
mullinax95 said:
No the choke does not have a cable to it. I might need to install rod to hold the choke plate open matter of fact. .
Click to expand...
And here is the biggest problem.
Once you have correctly installed your carb, come back and ask the question again.
Until this time, your wasting our time and your own.

IF YOU DO NOT FOLLOW INSTRUCTIONS AND HAVE A PROBLEM, THEN YOU ONLY CAN BLAME YOURSELF. GO BACK AND FOLLOW THE INSTRUCTIONS AND PURCHASE A MANUAL CABLE FOR THE CARB.

Also, the second sentence, do not install a rod. Do it right the first time and avoid fires that will destroy the car, or yourself and God forbid, others.
Installing "A Rod" to prop open the choke is a Yaa-Hoo ID10T thing to do.
 
I agree, you need to connect the choke cable and play with it first. But also though you may be getting vapor lock. My trucks 360 would start on a dime cold but as soon as she warmed up a little and shut off, it'd have to be cranked for awhile then finally start up. Someone recommended a insulator spacer between the carb and that worked miracles. But connect the choke first.
 
Also what hole in the acc pump arm is the lever......it should be in the bottom hole so it give a full shot. It really sounds like a vapor lock problem......I had that on my car when it had the eddy carb......I hate that carb.....it all went away when I went to the Holley. It does sound like either vapor lock or fuel dripping in the intake.
 
Dusterb318 said:
Also what hole in the acc pump arm is the lever......it should be in the bottom hole so it give a full shot. n It really sounds like a vapor lock problem......I had that on my car when it had the eddy carb......I hate that carb.....it all went away when I went to the Holley. It does sound like either vapor lock or fuel dripping in the intake.
Click to expand...
Ditto. Where do you live? In Denver they change the fuels in the winter and add alcohol to gas and it makes vapor lock/flood problems for carburetor cars.
they may do that in your area. But I also dislike the eddy carb.
 
Good call on the fuel change 66Dartman.....you are exactly right with the alcohol addition in the winter.....that will also make you run lean along with the cooler air......might need a jet or metering rod adjusment too. Also you need to set your enrichment screws with a vacuum gauge and not by ear......set them so you get the highest amount of manifold vacuum and then put in the metering rod spring that corresponds with the vacuum reading. then you can start playing with metering rods and jets......I had an eddy carb on my car and could never get the stumble out of it.....but my engine is far from stock so I'm sure that has something to do with it.
 
rumblefish360 said:
And here is the biggest problem.
Once you have correctly installed your carb, come back and ask the question again.
Until this time, your wasting our time and your own.

IF YOU DO NOT FOLLOW INSTRUCTIONS AND HAVE A PROBLEM, THEN YOU ONLY CAN BLAME YOURSELF. GO BACK AND FOLLOW THE INSTRUCTIONS AND PURCHASE A MANUAL CABLE FOR THE CARB.

Also, the second sentence, do not install a rod. Do it right the first time and avoid fires that will destroy the car, or yourself and God forbid, others.
Installing "A Rod" to prop open the choke is a Yaa-Hoo ID10T thing to do.
Click to expand...

DANG I DIDN'T MEAN TO PISS YOU OFF A**HOLE!

I didn't install the carb it was already on the car when I bought it. And I have seen a number of cars that had a rod installed to keep the choke plate opened and from having to run a ugly choke cable. I saw one in the Mopar Muscle mag before.
 
GSS340 said:
I agree, you need to connect the choke cable and play with it first. But also though you may be getting vapor lock. My trucks 360 would start on a dime cold but as soon as she warmed up a little and shut off, it'd have to be cranked for awhile then finally start up. Someone recommended a insulator spacer between the carb and that worked miracles. But connect the choke first.
Click to expand...

I would connect the choke but I have never needed one before. I always have just hit throttle a few light hits and turn the switch and the car would come to life. It does not get very cold down here in SC. I always have held the gas open just a little bit to get the motor warmed up and off I'd go. Most of the guys around here just remove the choke plate altogether and some I've seen cut the top part off (Holleys).
 
I live in Michigan and just this last weekend I went down 1 jet size on my Holley hp 750 seconardys cause it felt not as crisp as before and yeah the motor is back like it was. Thats funny cause 2 months ago I need to jet the primary side up 2 from 71's to 73 cause it felt a litte lean part throttle. Motor is running now just great--wish the snow and salt would never come-I even drove it today when it was 28 degress outside, I floor it 2 times and it starts right up, rev. it for 10-15 sec. and drive off, it has no choke-its a hp carb. The rest of the day it starts just fine, if its off for over an hour I just need to floor it half way once then crank. I think its in your carb. and or spark box. 2 winters ago when I had the MSD 6 box it start ok but stall once or twice but now with the MSD 7al and 8251 coil its almost like a new car--well expect for the 14" of vacuum at idle but its a good strong idle and never stalls out. I never had an Eddy carb so not sure whats wrong. If got got the $$ though I would get the Holley HP carb and a MSD 7al box but yeah that stuff is not cheap. I got my Holley then 5 years latter I upgraded my spark box. I am so glad I did looking back. Good luck
 
mullinax95 said:
DANG I DIDN'T MEAN TO ........
Click to expand...

Easy guys! This is starting to get ugly.... =;


More than likely one of us could fix it IF WE WERE THERE! But were not, so this is pretty much a crap shoot from everyone involved. My suggestion is to seek a local guy who KNOWS carburetors and older cars. Diagnosing something on-line is always difficult and leads to spirited discussions, such as this is becoming. Various people have different skill levels and approaches to trouble shooting. I suggest Mulinax seeks someone whom can actually lay their hands on the problem in person. At this point there's too many different directions to go in.:thumrigh:
 
DID ANYONE READ THE BIT IN MORPAR MUSCLE ABOUT THIS PROBLEM they said that the gas we have to day is different than when our cars were new an the reed vapor is lower and the gas evoporates faster and the gas in the float bowl go away much faster this has been a problem for all of us in the local car club some of us put an fiber block under the carb. end of hot start problem but not end of problem after 3 to 5 days of not running
 
I had the same problem with my edelbrock on my truck,cold it would startup fine.when I try to start it when its warm,forget it, its flooded.I had to hold the accelerator to the floor to get it going.I never did figure it out,but all most everyone else that uses edelbrock carbs has the same problem.I lived with it until i sold the truck.
 
When the engine is hot and you are having trouble starting it does the cranking slow down as though the battery is a little weak? If so it is a sign that your initial timing is a little too advanced. Back it off 2° and try it again. If it still cranks a little slow back it off 2° more and so on.

I set my idle mixture from scratch like this:

Fire it up and hold the throttle open to keep it running for a couple of minutes. Once it is a little warm slowly release the throttle. If it starts to die, slightly tap the accelerator pump arm and see what happens. If it improves you are a little too lean so back out the idle mixture screw 1/8 of a turn. If it gets worse or craps out you are a little too rich so turn the idle mixture screw 1/8 of a turn in. Keep tapping and adjusting until it is idling good at the correct RPM and the slight taps have little or no effect.
 
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