67 427 will not idle

[Bob H.]

I just purchased a 67 427 435 car and I can't get it to idle.

Off the idle it runs terrific. The car did come froman elevation of 4500 ft and I'm near sea level. If you idle it over about 1400 it will continue to run steady. As soon as I try to idle it down it just quits. Looking iin the carb I can see fuel dripping from the center circles UNTIL I start droping the RPMS. It looks like at some point there is no fuel and the car slowing dies. If I hit the throttle the acelerator pump squirts and the car revs back up only to die. I removed the needles and shot carb cleaner and also tried reving the car and putting my hand over the center carb to no avail.

Any ideas? I was wondering about a power valve but wouldn't it run rich? It doesn't seem to be rich .

[Marco H.]

Re: 67 427 will not idle

Bob,
It sounds like the idle circuit might be clogged. Has the car been sitting for a period of time?? It seems the car runs as soon as the carb is on the main circuit. Inside the air horn are some small "vents" along the front edge; try to spray some carb cleaner down into them, and maybe some compressed air. Also check the float level, just to be sure.
If that doesn't help, I would remove the carb for a thorough cleaning. Especially if the car has been sitting and the carb was dried up.
Hope this helps.
Marco

[Jim T.]

Re: 67 427 will not idle

Bob if you remove the air cleaner lid, have someone start the car and get it down to the lowest RPM, then put your finger over the vertical vent on the carb.
If the engine dies within a few seconds, the power valve is ruptured.
It is an easy fix, you can usually buy a Holley power valve, metering block gasket, and fuel bowl gasket from auto parts stores. I have bought them from Auto Zone. The newer blue Holley gaskets are reusable unlike the older ones.
With the metering block off you can use a spray can of Gumont with an spray tube to get into the passage ways and clean them.
The accerlator pump gets stiff with age, new one is real flexable, something else to check and buy.

[Bob H.]

Re: 67 427 will not idle

You guys are great!

When I pulled the needles and sprayed cleaner it came out those small holes.

However while screwing around with it, I did put my hand over the tube on the front center of the and it did die out. I guess this is what you are talking about.

The car has sit a good bit. I had also checked the float level and it was good.
Sounds like I need to pull that carb. Do you have a reccomendation for a power valve or should I just replace it with what is in it?

I now feel better about proceeding with the carb rebuild.

Thanks guys.

[Stephen L.]

Re: 67 427 will not idle

If you are replacing the power valve you may want to also install the power valve check valve. It keeps the power valve from failing due to backfire of the engine....

[Bob H.]

Re: 67 427 will not idle

What a pain to get the center carb off. I just replaced the power valve with a 6.5, cleaned the metering block etc. It did not have any effect on the problem It does have 66 jets in it. the metering block I'm told is incorrect. It had a number of I believe 5101 on it.

[Stephen L.]

Re: 67 427 will not idle

You may have a vacuum/manifold leak which would allow excessive air into the manifold upsetting the fuel mixture (lean) to the point that it quits. At higher RPM the leak becomes insignificant.

You might try sqirting a small amount of water at the gasket areas of the manifold to see if it gets sucked into the engine....... Also check vacuum hoses for leaks.

[Bob H.]

Re: 67 427 will not idle

Thanks Stephen

It does act that way. I'll try that tomorrow.

Bob