Carburetor gasket dangerous fiasco

[BAsque1]

Gentlemen:
Beware of this problem (perhaps someone has had this experience), Saturday afternoon while having a relaxing drive with my son, the engine of my car started to rev up excessively. So as to avoid blowing the engine and place ourselves in a very dangerous fast driving situation immediately I turned the key off and coasted to the shoulder to inspect the problem.

At first glance all seemed normal the idle adjustment screw of the Holley 770 carb was fine, the choke was not sticking, nothing was binding preventing the carb to function normal, but each and every time I tried starting the engine it went up all the way to 3500 rpms. I had the car towed home and with fingers crossed that nothing major was going on.

Yesterday we started checking things around and eventually I decided to pull the carb off, to our amazement, the gasket between the carb and the phenolic spacer center was broken and a tiny particle had lodged in between the secondary venturies throttle plates keeping them from fully functioning, hence causing the excessive elevated rpms.

The gasket fragment was removed and the carb operated normal, we installed back in the car and worked fine again.

My biggest concern was our safety when all of a sudden the acceleration went out of control, hence at the risk of sounding patronizing to anyone please be careful and enjoy a safe drive. Our cars could be very unforgiving due to their awesome power.
Sincerely
Lou

[mrmustang]

First, thankfully you had the right mindset to turn off the engine and stop safely.

What intake do you have on your car?

I ask as sometimes the gasket (in this case your square bore quad opening) is not right for the application. If your intake is an open or split plenum unit (see attached picture)


then an open gasket like this

or this


would be the suggested carb gaskets for that application.

Hope you find this helpful.

Yours In Fords,


Bill S.

[Ron61]

Lou,

That would be scary. Glad that everything turned out well and that it wasn't some major problem. As Bill said, at least you had the presence of mind to turn the engine off immediately.

Ron

[BAsque1]

Tks guys for your kinds comments. Bill my intake is the 4 type as the picture of the gasket. I think we should use this as "Sticky" if you asked me, sometimes cars can blind sight us in their "behavior" .
I never forget a 67 Ford Cortina GT I had fitted with a dual OHC from a crashed Lotus Super 7. Every time I turned right on to a steep hill curve the car would die as if starved out of gas.
After extensive mechanical forensics, then, my Dad had the vision to pull the gas tank out, to our surprise someone previous to my ownership had a dropped a small piece of fabric in the tank that would slide with the surge to the gas pick up every time I turned.
Once removed the problem was corrected. But sometimes they will stump you.
Thanks again guys
Lou