70 Challenger R/T 383 hard start when hot

Author Topic: 70 Challenger R/T 383 hard start when hot  (Read 1339 times)

Offline Mc MOPAR

  • Jr. Member
  • **
  • Posts: 39
70 Challenger R/T 383 hard start when hot
« on: May 12, 2015 - 06:20:34 PM »
Hey guys,

I finally got my 1970 Challenger on the road, and I am working through a few bugs.  I am amazed at how nice this 383 starts up when the engine is cold, it’s almost like fuel injection just turn the key and it roars to life.  The problem is starting when it’s hot, it’s like it floods itself when I shut it off.  The only way I can get it started when hot is to put the gas pedal to the floor and turn it over for about 2-3 seconds and then it fires up.  It’s a little embarrassing because people really love the car, I get comments and thumbs up all the time.  But then I go to start it and it almost sounds like it’s not going to start at first.  My first thought is it’s running way to rich, but I wanted to see what you guys thought before playing with the timing and jets on the carb.




Offline Rich G

  • Jr. Member
  • **
  • Posts: 355
Re: 70 Challenger R/T 383 hard start when hot
« Reply #1 on: May 12, 2015 - 07:30:49 PM »
When you shut it off when its hot look down in the carb. Is there gas dripping in. Floats could be a bit high and the gas could be boiling in the carb. I put one of those Cool Carb plates under the carb on my hot rod truck to prevent that. Just a few things to check.

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: 70 Challenger R/T 383 hard start when hot
« Reply #2 on: May 12, 2015 - 11:13:46 PM »
it has to be set rich , it should be harder to start cold & is flooding hot , check float levels first

Challenger - You`ll wish You Hadn`t

Offline Cuda Cody

  • Resident
  • *****
  • Posts: 3988
  • Vancouver, WA
Re: 70 Challenger R/T 383 hard start when hot
« Reply #3 on: May 13, 2015 - 01:53:14 AM »
When you shut it off and immediately start it back up is it hard to start or is it after it's sat a few minutes then it's hard to start?
The funniest thing about this particular signature is that by the time you realize it doesn't say anything it's to late to stop reading it.

Offline Mc MOPAR

  • Jr. Member
  • **
  • Posts: 39
Re: 70 Challenger R/T 383 hard start when hot
« Reply #4 on: May 13, 2015 - 07:08:10 AM »
I’ve never tried starting it right after shutting it off, so I will try that and see what it does.  I will also pull the air breather and look down the carb after shutting it off when hot, and see if there is gas dripping down into the intake manifold.  Thanks for the suggestions on things to check, I’ll let you know what I find out.  I’ve been reading about hot flooding, and I think that’s what is probably going on here.

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: 70 Challenger R/T 383 hard start when hot
« Reply #5 on: May 13, 2015 - 09:00:01 AM »
Make sure the choke is open when hot also

Challenger - You`ll wish You Hadn`t

Offline Mc MOPAR

  • Jr. Member
  • **
  • Posts: 39
Re: 70 Challenger R/T 383 hard start when hot
« Reply #6 on: May 13, 2015 - 01:54:21 PM »
Yes thats actually the first thing I checked because I have a 340 engine that used to do that, it would start up great when cold but then was hard to start when hot and it turned out the choke would never open up even when hot.  So I eventually just disconnected it, and I tried that with this 383 but it didn't change anything other then it was also harder to start when cold, so I hooked it back up.