Car hard to start when HOT

[1970Dart198]

It's Summer, and my 1970 Dodge Dart with 198 slant six has a difficult time restarting AFTER I've driven the car not too long. The Temperature gauge is accurate and it goes through the roof after only a few miles.

My concern is that the car will turn over and crank, but it won't light and actually vroom. I was told that because the car runs HOT the choke stove attached to the carburetor acts differently and holds the choke open.

I just ordered a whole new cooling system: Thermostat, Water Pump, Heater hoses, and all the gaskets to go with them.

I plan to drain the coolant, remove the ORIGINAL radiator, bring it to a radiator shop to put it in this cleaning "bath", and remove and replace the ORIGINAL thermostat, ORIGINAL water pump, and hoses.

The car starts fine if I leave it for a few hours or overnight to cool, but if you're like me who uses the car as a daily driver during the summer, Starting and restarting is a must.

Thanks!

 

[bad440]

sounds like you got it covered,if you still have points you should get a trailbeast kit and you will be golden....

 

[green72]

And if you still have problems get a newer style starter. This was by far the best thing I did to improve starting!!!

 

[RustyRatRod]

To heck with diagnosis, just throw parts at it.

 

[moparlover]

hard livin will do that to a car lol.

anyways... sounds like you have two separate issues. first is the cooling system. please remember that the block water jacket is part of the "system" and is probably clogged to hell. someone could have even added to the problem with stopleak. before putting on any new parts you need to flush it with a cooling system cleaner of some type. then flush it again. maybe 3 times for luck. then put your new radiator and other parts on. you dont want a bunch of sediment in your new radiator do you? make sure you fill with 50/50- premix dont use tap water.

second issue. could be gas supply OR ignition related. if the vacuum advance hose is cracked or rotten it will have a hard time starting. you might not notice it cold because you are getting the extra boost of gas. when working properly, a mopar will click - fire over - vroom very fast in the morning... my 340 always did, it cranked for about half a second before firing. once warmed up it might take a second and a half.
if it's gas supply... you probably have sticking choke linkage and/or the carb needs a good cleaning & rebuild. after years and years it gets all varnished inside, and that stuff builds up on jets, float seats, in the orifices etc.

summary: check vaccum advance hose for cracks/replace. rebuild / clean carb. flush cooling system well before installing the new parts.

http://www.autozone.com/autozone/ac...ator-flush/_/N-262g?itemIdentifier=525741_0_0_

 

[VDART]

did you search fuel line mod for aslant 6? basically your boiling the fuel out of the metal lines that the factory routed close to the block. use rubber fuel hoes to go over the top of the valve cover & it will help the hot start issue . Lawrence

 

['73red-duster]

Check your timing too. Out of time, can cause it to over heat, and make it hard to start once it gets hot. I know this from experience.

 

[Oldmanmopar]

This is a common problem a lot are having. Add a return to the line from the filter. Same filter used on 1987 dodge truck. This will stop the fuel from seeping in from pressure after shutting down. The fuel today with ethanol has a lower boiling point. To see if this is it . Crack the line and relieve the pressure after shutting it off . Wait a little while and retighten it and start it. A lot of carburetor cars are having this problem.

Fuel dead ended at the carb will not work correct with fuels today. This has been covered several times in other threads.. Put some c16 race fuel in it with some lead and top lube added this will also fix the problem.

 

[scottylack]

vapor lock vapor lock vapor lock!

 

[cudavert]

As was mentioned......most likely fuel percolation, then flooding. BUT, could also be ignition related. If mine, I would just do a voltage check on the "+" side of the coil while cranking, just to make sure it's getting bypassed boosted voltage.....full 12v. Also, check your point gap. If it's way too small, you can have hard starting problems.

That is....if you're still running points.

 

[68383GTS]

Drive it around and get it warm.Then shut it off and take off your air cleaner and put your ear up to the carb. and listen to see if your hear the gas boiling.If so make sure your gas line is away from everything hot,even the valve cover.I had this same issue with a 71 Fury 383.

 

[TylerW]

And if you still have problems get a newer style starter. This was by far the best thing I did to improve starting!!!

Chrysler thought of that first. When engine temps started going up in the 70's and engines began getting harder to start, they redesigned the starter to increase the cranking speed to mask the long start.

Same thing happened again when they brought out the large-frame starter in '74.

The new mini-starter spins the same speed as the large-frame starter. Since it sounds different it impresses people that it works better but in all likelyhood, it isn't.