hard to start when hot

[red 69 runner]

I have a 69 road runner with the original 383,VIN is stamped on the block.Odometer shows 21,000,I am quessing that means 121,000.The motor runs strong and dosent smoke,the previous owner replaced the valve seals and installed an eldebrock 750cfm carb,the engine starts right up when it is cold but after runnung the car and everything is up to normal operating temp if I shut it off and then go to restart it after say 15 or 20 minutes the engine cranks and dosent start right up unless I put the pedal down about 1/4.Is this a carburator issue or maybe the ignition ,the original points distributer is still in the car but I just bought a electronic distributer kit from mopar performance but havent installed it yet.I am just getting back into older cars and have forgotten alot from when I used to work on my own cars back in the day.any sugestions I would greatly appreiciate..

 

[NDBSRT8]

when you crank it does it sound like you have a half dead battery?

 

[bigmanjbmopar]

I was in your shoes just this past summer. the 383 is all stock? if he put in valve seals in new were the valves adjusted properly? We had mine hanging open and when it got hot it would not idle well and would die and take almost full pedal to start.

If not valves then fuel float on the carb. get the pdf copy of the book from eddy's web site and follow the directions on adjusting the floats. my brand new 800 had 1 float pegged to the deck and needed adjusting. Also try insulating the carb with a heat resistant gasket. Some times with the new gas we have you can get fuel boil caused by excessive heat.

Like stated make sure battery is charging.

 

[johnhinds]

seems like i read on 62-65 mopar site, the hot engine boils the fuel out of the fuel pump, causing hard starts. I don't know but it is possible. my 65 383 does the same thing. I can pour a little gas in the fuel bowl's and it will start right up. it might be boiling it out of the carb.

 

[red 69 runner]

Engine cranks very fast,battery is charging .I saw another thread after posting this question and it seems since the heat cross over is still in tact and not blocked off the gas boiling out might be the problem.I forgot to mention i brought the car from a high alltitude probably 2500 ftor higher to maryland where i am about 75ft above sea level.there is no problem with idleing cold or hot but when i bring it in and park in the garage after driving it for probably an hour there is a strong odor of gas in the garage until the engine cools down.if I blank off the crossover will the only draw back be longer warm up time?

 

[carolinadoug]

Hot Start

I have had the same problem on my '70 Satellite. I have a 600cfm Edelbrock carb on a Performer RPM intake on a 383. The combination runs beautifully but when it has been shut down for 15-60 minutes it is very difficult to start. If I stop for gas (which i do frequently) it starts right back up. The engine starts right up cold and idles perfect both hot and cold.

I have been researching the problem and have tried changing the idle mixture and timing (in both directions). Neither had an effect so I went back to the original settings.

I have read in several places about the fuel boiling issue. My understanding is that due to the low boiling point of modern fuel the heat that rises from the engine thru the aluminum intake and aluminum bodied carb causes the fuel in the bowls to percolate and essentially flood the engine. This explains the gas smell you mentioned (I smelled it too). I also learned when I smelled the gas I could hold the throttle wide open when I cranked it hot and it would start right up which is a symptom of a flooded engine. If thermal transfer is causing the problem I am not sure if blocking the crossover would solve the problem or not. If you try it and have success please let me know.

I did buy the Edelbrock carb insulator (http://www.summitracing.com/parts/EDL-9266/) and install it about a week ago. It seems to have helped the problem. One other thing I read is that this boiling problem causes the engine to flood very easily so you should not even breath on the throttle when you start it. If you crank for 2-3 seconds and it does not start SLOWLY push the throttle to approx 25%, trying to minimize how much fuel is being pushed thru the accelerator pump.

By using the insulator and the no/light throttle starting method the problem is basically gone although I have had to crank for a few seconds longer then I should have once or twice.

Hope all this helps and let us know what happens.

Doug

 

[okiemopar]

It is the gas purking out of the carb. I have had old and new Edlebrocks and they all purk. With my air grabber I can't put a spacer under it so I just make the best of it. It always starts so I'm not going to worry about it. Ronnie

 

[red 69 runner]

I think I will try the insulator first and see what happens,your problem is exactly like the one I am haveing,stopping for gas it starts right back up.I am running the original cast iron manifold,I was thinking of going to an aluminum one but you are running one with the same problem so I will wait on that up grade,also the info on checking the floats from bigmanjbmopar is something i am going to do.Maybe its the edelbrock carbs,maybe try a holley.

 

[68sportsatelliteragtop]

I think I will try the insulator first and see what happens,your problem is exactly like the one I am haveing,stopping for gas it starts right back up.I am running the original cast iron manifold,I was thinking of going to an aluminum one but you are running one with the same problem so I will wait on that up grade,also the info on checking the floats from bigmanjbmopar is something i am going to do.Maybe its the edelbrock carbs,maybe try a holley.

I've had the same issues all summer with my car and it is Holley equipped. I don't have enough clearance for the 1/4" isolator as my air cleaner top already rubs the pad under the hood. Starts best with 1/2 throttle while cranking. Now with the cooler weather, fires right up. I run an MSD and opened plug gap up to .050, that seemed to help also.

 

[GTXTHUNDER]

Hello, I had the same problem with my 67 GTX. I ran into a guy at Carlisle that said he could solve my problem. I bought one on the spot. Long story short, it works. Go to WWW.coolcarb.com. Hope this helps.

 

[tpodwdog]

its the nature of the beast. i had 2- 70 roadrunners in my day...both with 383's . the one i have now( <<<over there) ..does the same thing as the one i had back in the 80's. i have learned to live with it and neither of them EVER let me down !.

 

[bigmanjbmopar]

I use the eddy thick heat gasket and a 1/2" aluminum spacer I know sounds funny adding more aluminum but with the heat spacer the 1/2" spacer and another thin paper gasket my perk issue has vanished. along with a little space. But now I use a 2" re usable filter and a low profile 14" pie tin.