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Dies at idle, only when hot
https://slantsix.org/forum/viewtopic.php?t=63618
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Author:  1963dodgedart [ Tue May 14, 2019 6:27 pm ]
Post subject:  Dies at idle, only when hot

Hi,
2000 miles ago I rebuilt a 1963 225 /6 motor.
After my first long trip across California, it now dies at idle only when hot.
It starts up and runs perfectly when cold, and it runs perfectly at freeway speeds, but as soon as I come down to idle it dies unless I give it gas.
Once it does stall, I need to put my foot all the way to the floor to get it to start again.
I drove it 400 miles home, and the MPG did not change noticeably.

It is stock, except for Petronix ignition and coil. 8mm wires. No resistor.
Carter BBS carb, rebuilt (by someone else) 1500 miles ago.
Timing good (10).
Compression good both cold and hot enough to die.
No water in oil, no disappearing radiator water.
Valve clearances good (hot running)
Flipped coils, no change.
Changed fuel filter.
Replaced spark plugs.
I can't -see- any cracks in the manifolds.

My next thoughts are to take apart the carb, but worried i won't see the problem when I rebuild it cold.
Put the old points in to test...

Any thoughts?

Thanks,
Ben

Author:  Charrlie_S [ Wed May 15, 2019 4:08 am ]
Post subject:  Re: Dies at idle, only when hot

Sounds like you have a "hot soak" flooding problem. Make sure of the float level, and that the bowl vent is set right.

Author:  Louise76 [ Wed May 15, 2019 8:28 pm ]
Post subject:  Re: Dies at idle, only when hot

If you have to open the air valve (throttle) wide to re-start it hot, then it is definitely too much fuel, not enough air that is killing it.

Author:  Joshie225 [ Wed May 15, 2019 9:53 pm ]
Post subject:  Re: Dies at idle, only when hot

Take off the air cleaner and look down the carburetor throat when it's hot and idling. If you see fuel dripping from the booster venturi then the fuel level in the carburetor is too high for one reason or another. For me, today, it was a tiny sliver on the seat keeping the needle from seating properly. I was able to close the idle mixture needles and have it stay running. :?

Author:  1963dodgedart [ Thu May 23, 2019 11:23 am ]
Post subject:  Re: Dies at idle, only when hot

Well,
This is still driving me crazy.

I sit at idle in the garage and it takes 15-20 minutes for the car to get hot enough to start badly misfiring at idle.

I took apart the carb, blew through everything, double checked the float, put it back together and it still does the same thing.

Just to be paranoid, I put the old points back in, (new resistor) with the old coil, old rotor, changed the coil-cap wire, and it still does the same thing.

It's weird, sitting at idle, it runs perfectly, and then suddenly it does not, it is like there is a sudden switch that makes it change.
The float bowl feels cool to the touch, I have the fuel filter over by the alternator.

I'm getting so frustrated, I'm thinking of buying another carb just to put it on and see what happens....

Author:  drgonzo [ Thu May 23, 2019 11:37 am ]
Post subject:  Re: Dies at idle, only when hot

When the engine dies, is there fuel in the carburetor bowl at that point?

Author:  Joshie225 [ Thu May 23, 2019 12:20 pm ]
Post subject:  Re: Dies at idle, only when hot

The float level can measure correctly and still not control the fuel level if the float itself is bad. Did you look down the carburetor throat with the engine hot?

You could also have an electrical problem. Have you disconnected the bulkhead connector and examined the terminals for corrosion or signs of overheating?

Author:  1963dodgedart [ Thu Jun 06, 2019 11:07 am ]
Post subject:  Re: Dies at idle, only when hot

Hi,
For those keeping track at home...
I have spent the last couple weeks threatening to turn her into a boat anchor.
I finally came to the point of just replacing parts...
The last thing I replaced was the spark plug wires and the air filter.
Now she runs perfectly...
(I had replaced just the coil-distributor wire)
Can't be the air filter as she ran badly with the air cleaner removed...
so it was the spark plug wires.
I had Taylor Cable 8mm wires and replaced them with generic AutoZone 7mm and...
She runs great.
1000 miles for the Taylor Cable spark plug wires to fail...

Blah!

Ok, I'm going for a drive.

Thanks!

Author:  Dart270 [ Thu Jun 06, 2019 1:06 pm ]
Post subject:  Re: Dies at idle, only when hot

Wow, nice result. The Slant 6 does not need fancy plug wires since there is no exhaust heat on that side and all plugs and dist terminals are well separated. Enjoy the drive!

Lou

Author:  Louise76 [ Fri Jun 07, 2019 9:56 am ]
Post subject:  Re: Dies at idle, only when hot

Thanks for keeping us in the loop: we all learn.

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