[rcchalmers]

I have a 67 6 cyl, 3 spd manual, just installed factory carb w/ auto choke. Starts great, runs great, just about dialed in. However, if it ever stalls hot, it won't fire up unless I get out and manually close the choke plate, then it starts right up.

Timing is dead on 6 deg btdc, checked choke plate clearance, think that's right - but tried opening and closing, played with rich v. lean to no avail. Any ideas?

 

[rocky289]

Does it idle ok hot?
Is it getting squirt from the accelerator pump?

 

[joef21]

I would look for a vacumn leak or bad acc. pump.
I have been told that the 6 cyl cars are bad for craking the manifolds.

 

[faststang68]

I have a 67 6 cyl, 3 spd manual, just installed factory carb w/ auto choke. Starts great, runs great, just about dialed in. However, if it ever stalls hot, it won't fire up unless I get out and manually close the choke plate, then it starts right up.

Timing is dead on 6 deg btdc, checked choke plate clearance, think that's right - but tried opening and closing, played with rich v. lean to no avail. Any ideas?

-----------------------

Hmm, thats a tough one. . Just curious, have you tried to disconnect the electric choke ? To see if it does the same thing ?

 

[rcchalmers]

67 won't start

Thanks to all for the replies. Here's some of the answers:

1) Carb is remanufactured new, so I don't suspect the accelerater pump. Plus it only has a problem when hot.

2) Have not measured vacuum, but I have gone around and sealed all suspect areas. Is there a vacuum spec and how would one measure this?

Last note, I have been running without the air cleaner for diagnostic purposes. Put it back on just in case and it helped a bunch. Thought I had it licked - then it was really warm yesterday, it stalled and then would not restart until i manually choked it. But having the lid on definitely helped.

 

[rcchalmers]

67 won't start

Almost forgot. No electric choke, just spring operated automatic choke.

 

[PaulS]

If it cranks when hot but not starting then replace your gas cap first - with a vented one. Replace all the filters and make sure the fuel line doesn't come close to the exhaust. Check the settings for floats, timing, and idle mixture.

 

[rcchalmers]

67 won't start hot

PaulS thanks for the reply.

Have checked timing - dead on. Have not tried gas cap, but will. The fuel line is well away from heat sources - was worried about this myself. Brand new fuel filter. BTW, runs great and idles great even when hot.

Hesitates on acceleration slightly. If you are not a good manual transmission driver...it can stall.

With regard to idle mixture, how do you check this? This is the one area I think is not quite right.

 

[PaulS]

To adjust the idle mixture you first set the idle stop at the correct idle speed, then you start with the idle mixture screws 1 1/2 turns out from a gentle seating closed. Adjust them (using a tach) to get the highest rpm you can moving each idle screw the same amount. Reset the idle speed to where it should be and repeat the process until the idle is as high as it can be then turn the idle mixture screws rich 1/8 to 1/4 turn as long as the idle stays smooth.
That should get you very close to the right mixture.

 

[rcchalmers]

67 won't start hot.

PaulS,

Thanks again for the help. I'll try that.

 

[Joel_L]

How's the float level, too low? Is the carb itself getting too hot ( vapor lock in the carb ). Sounds like the fuel lines are clear of heat sources.

 

[rcchalmers]

67 won't start hot

Thanks Joe L for the suggestion. I have not checked the float level, etc inside the carb becasue it is refurbed out of the box - just put it on.

Last night I messed around with it some. The problem is hesitation when you first push the accelerator - a flot spot if you will. You can push past it with high revs, but it's not right. I did two things that seem to help.

I shielded the gas line anywhere it was less than 2 inches from the exhaust (two places). Believe this is just a precaution, the lines were warm, but not hot to the touch.

I also advanced the timing to about 12* btdc. This is the top end of what my shop manual specifies. This AM it ran great and the flat spot seems to have gone away, but it was cool outside.

Still no explanation on why it won't start after it stalls when hot - unless the choke is manually closed.

I do notice that the carb feels warmer than I think it should. Next up is to look for a phenolic spacer to act as a heat insulator - anyone have any ideas on where to find something like this?

 

[Boidster]

About 9 posts down in this thread at hotrodders.com there's a good overview of all the systems you need to check, and how to check them. The thread originally was about a flat spot during acceleration, but mistuned systems could probably cause a host of issues including poor starting when hot.

Maybe it'll help.

Edit: the thread above is just a C&P from this article at tuningmadeeasy.com. That site also has a "part 2" that goes into more detail about jets.

 

[rcchalmers]

Thanks Boidster,

Found out that the 1100 Carb has two Acc pump settings. Moved up to the "high" setting and it helped. Even better than before when cool to warm. Still rough when it's hot. Must be vapor lock.

I'm gonna try to insulate the fuel line from pump to carb and a spacer under the carb.

Any other ideas?

 

[mustang402]

Just wondering, did the insulator help? sounds like you might be perkulating the fuel in the carb after you shut off the engine after a drive. After a 15-20 min or so drive shut off the engine,take the breather off and see if the squirt nozzles are dripping down the throttle body. Autolite and edelbrock carbs are bad about this issue since the fuel bowls set low and on the bottom of the carb body. Holleys don't seem to bother with this issue so bad since the bowls set different in their carb body. Ford solved it by placing an insulator under ther carbs.
HTH