340 has a hard time starting when hot?

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agepag

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So driving my fathers 340 dart, every time I take it for a drive and park it, I cannot start it? Usually I take it to the local car show, car runs abit hot, but after sitting for 1-2 hours its really hard to start? Any suggestions....

THanks
 
a couple things come to mind , you may have a heat soak problem where the gas is boiling the carb dry or maybe even a faulty coil . a few more details may help pinpoint it .
 
It sounds like heat soak on the starter, or the starter &/or starter relay is going south.
 
After shut down before you try to start it, open the air cleaner, look down the bores, and give the throttle a pump. Fuel shot should be almost instant.
 
Ethanol based gas evaporates out of the bowl when hot much faster than non-ethanol.
 
If your running headers on the engine, how close are the tubes to the starter? Will cause heat soak on starter and starter will not crank until it cools down.(IF you have headers)
 
I'm not that good with Thermoquads yet, but if it is a TQ, could it be dripping/leaking fuel internally and basically flooding the engine after it's shut off?
 
If its a factory starter it is bigger than a mini- starter. A lot of guys run a Dakota truck starter it is way smaller and gives better clearance from the hot headers.
 
im not sure eightys or nintys hopefully some one will chime in 84-95 ish?
 
Shoot, we don't even know if it cranks slower when hot or just doesn't want to fire.
A little diagnosis would go a long way to helping with this, instead of it going into pages of guesses.

What is actually done to finally get it started?
Is the throttle involved at all when trying?
 
Shoot, we don't even know if it cranks slower when hot or just doesn't want to fire.
A little diagnosis would go a long way to helping with this, instead of it going into pages of guesses.

What is actually done to finally get it started?
Is the throttle involved at all when trying?

So after driving for a while, then letting it cool down (at least 1 hour) I try to start it and just keeps cranking, same as usual, i try to pump the gas, but don't want to flood it. Its really strange/embarrassing..... guys are starting there cars and leaving and im sitting in the parking lot trying to start my car!! Also don't know if this makes any difference/sense, but the engine does not have a thermostat. I was told the block was machined so its no longer there?
 
So after driving for a while, then letting it cool down (at least 1 hour) I try to start it and just keeps cranking, same as usual, i try to pump the gas, but don't want to flood it. Its really strange/embarrassing..... guys are starting there cars and leaving and im sitting in the parking lot trying to start my car!! Also don't know if this makes any difference/sense, but the engine does not have a thermostat. I was told the block was machined so its no longer there?


You should run a mini starter no matter what. Unless it's a numbers matching resto car show deal. Even then, I'd have a mini starter sitting there and aftert he car was judged I'd put the mini starter back in. The big starters are just not that good.

What carb do you have? As Alaskan T/A said above, ethanol in the fuel will evaporate much quicker. Especially if you have a Carter/Edelbrock carb where the fuel bowls sit right over the intake manifold. Way too much heat there.

If that is what you have, you can use a plate under the carb. I think the best one is a carb cooler or something like that. I've been going to try one, just haven't got to it yet. IMO, that looks like the best option for that.

The second thing I always do, and have done since the early 1980's is block the heat off under the intake. That not only helps with what may be your situation, it will make more power.

I live in a high desert valley. So I get HOT in the summer and COLD in the winter. And I run a Strip Dominator. It has no crossover. So you can block the cross over and drive year round if you want to.

I've never ever had a carb freeze up IF, when it's really cold, you spend 5 minutes and build a bit of heat in the engine before you start to drive.
 
Yeah, if it's turning over fine with the starter, it is not heat soak.

My Sport Satellite had the same exact symptoms & it does have a mini-starter.

The fuel would boil out of the bowl after driving an hour or more & then letting it sit for a car show.

Once I figured it out (those long cranking sessions when trying to leave a car show do attract attention) I started using an old mustard bottle with gas in it to fill up the fuel bowl manually before trying to crank it.

In my case, switching to non-ethanol cleared it up with no other changes.
 
Pretty sure the 94 octane gas has no ethanol?


That may be true up there in the great white north, but down here, you have to find a place that has "clear" fuel or it all has ethanol in it.

Even so, with all that heat under the carb the fuel will evaporate out of the bowl very quickly even without ethanol in it.
 
Sounds like classic fuel evaporating problem, same thing with eddelbrock carbs.
 
I had the same issue with my Duster. Like stated above the fuel boils. Even after my car sat for 1 hr it was hard starting and when it did start it was flooded with fuel. I would have to turn the pump off and on until it received fresh fuel. On my car I had to change the regulator to a return style and put it after the carb. Pictures below. The car did not do this with leaded race fuel. Only on pump gas going to shows. After I change it over it ran more consistent through temp changes. What I did is what you would do on a holley dual feed line with electric pump.

On a carter style this is what you want to do.

Most mopar V8's from mid 70's and up had a return on the filter for this reason. There was third nipple on the side that would flow back to the tank. The float in the carb will not function properly with hot fuel of today when the fuel is dead ended up against the needle and seat while hot. Adding a return eliminates this problem. They added the return to the filter and routed it back to the tank.

How to check if this is your problem is . After the car is hot and before you go to restart it. Take the fuel line off at the carb. Put a hose on it and run it into a container. Turn the car over until fresh cool fuel comes out. Put the line back on and it should start. I have done this 3 nipple filter on several cars that come here with this problem.

A cool can also works but then you need to carry Ice and use a shut off for the fuel before shutting the car down.

This new fuel is terrible in our carbureted cars. It is the float not working in the carb that causes this issue

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On that dakota starter, i have a 71 318 in a 74 duster, i bought one for an 89 dakota v6, just make sure it has 2 bolt holes, most rebuild starter /alternator shops can tell you the part number
 
92 starter on my 367
As to the fuel, I run 87E10 full time with zero problems.
And the only band-aid is a hole in the hood feeding fresh cold air to the 750DP, on the AG intake.
However, my combo did not have a serious problem before the modification.
The carb itself is still sitting in the hot as Hades underhood environment.
I run Aluminum heads and a minimum coolant temp of 205*F and don't forget the un-wrapped TTI headers. So it gets really really hot under there.

Click-Vroom every time.
But she's a more or less DD so the fuel is always fresh.
Take a fuel sample; it needs to be from clear like water to yellowish. When it gets to the Orange stage, yur gonna have trouble.I Run fuel-stabilizer in all my Lawn N Garden stuff, that sometimes sits for weeks before the next usage.

I run a mechanical pump and 3/8 line, no choke. The EFI filter is back at the tank, with a one-piece home-fabbed line from pump to carb, no return. No carb spacer, no reflective wraps, but I do have an RPM AirGap. Click-Vroom, every time.

I live between the 49th and 50th parallels at 930 ft elevation. The hottest summer day is not likely to exceed 100*F but on occasion has. In summer it hovers around 85/95; a paradise it is;for about 8 weeks,lol.
If you suspect the carb, and it's a Holley; Drain and capture the fuel from the front bowl;it should measure about 50cc of clear fuel.

The lightest elements of gasoline begin to boil off at 100*F, and the heaviest not until 400*F. Ethanol's boiling point is listed as 173*F.
 
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My car never did it unless you left it sit for 1/2 hr to 1 hr. Then when I went to start it to leave it it would have the problem. If I would leave the pump off it would fire right up and I would have to turn the pump off and on until fresh fuel came through. If I would turn the pump on first it would flood the motor and just crank while I held the throttle 1/2 way until it fired. The float would not close the needle with the hot fuel. I tried three different carbs . Proform, BLP, and a quikfuel. All did the same thing. After I eliminated the fuel being dead ended at the carb problem solved.

I would always sit at shows with the hood open. 100gph pump and regulator on 1/2 inch fuel line from tank to carb. This problem drove me crazy for a long time. We just finished a aluminum head 340 Demon and another iron head Duster. They do not have this problem for some reason. Tap the key on them and like my Duster .

Click-Vroom, every time. LOL> Some cars do have this problem that we get them here off and on.

I had one of those "Vroom" motors on my 20" bike when I was a kid. Click Vroom every time. Now unlike others I don't have my atmospheric pressure, temp, altitude, fuel mix, nor do I know my parallels at any elevation. My fuel was purple and I piss yellow. South end puts out different colors at times. What I can tell you is this is something to check when you run out of ideas.

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