[snuup408]

Just wanted to throw this out there...68 cat with 74 windsor. has performer intake and 2 barrel carb...idles erratic....plugged all vacuum hoses...and set timing with a vacuum gauge as best i could...read somewhere to cover the carb with your hands and if the engine doesnt die then you have a leak so i thought id try...went to cover the carb and the girl revved up so quick i was in shock...i must have put my hand back and forth like what the!!!!....hmmm...put the BS air cleaner back on no change...took it off no change...cover with my hand revvs up high...smother it and the car dies....so my question is...is there something im missing being a newbee... do i need to find the original air cleaner cause maybe the air cleaner i have is letting too much air in..i was going to adjust the choke in the morning but my thinking is...it starts fine where its set and runs...I dont know...strange but seems so simple....any ideas or jokes for me?

 

[snuup408]

hello again...still learning the car...yah yah ive had it for years and still learning..lol....i went out and found out the carb specs and its a 2 barrel made for a 289....now would that make it run rough at idle too? that little carb on a big engine?

 

[Fordblue]

The engine revving up up when you cover the carb sounds like you are increasing the vacuum signal on the carb and it is dumping in more fuel and your suspected vacuum leak is adding the additional air to make it speed up.

Try the usual trick of spraying carb cleaner around the base of the carb, especially behind it where you may have a vacuum port not hooked up or plugged up, as well as around the intake where vacuum ports are located. If the engine speeds up, keep spraying that area in smaller and smaller spots until you track down the leak.

Any one else have any ideas?

 

[Fordblue]

Also, too small of a carb shouldn't hurt the idle very much, unless it is WAY too small. It would mostly limit how well the engine can rev up to higher RPM's

 

[1969XR7Vert]

Vacuum leak.

 

[Cedar Rapids Ia]

I agree with ECI Bob, also check your base plate gasket...we've seen that in other posts this year.