[Robbiebaer]

I have a 1970 cougar xr7 351c. When I stop at a light and roll forward giving a litle gas and then accelerate harder the engine cuts out and then comes right back. My cougar book says it could be an air intake backfire but I don't know how that is even possible. Any help would be appreciated.

 

[greggieatthebat]

I'm not an expert, as I've never successfully tuned a carb, but assisted in a few and read lots of books.
Experts please correct me!
Sounds like carb bog? Either too big of an accel pump, or incorrect power valve (wrong vacuum rating)? What kind of carb do you have?
Experts, does ignition timing affect bog too?

 

[TheRktmn]

In my experience timing will aggravate a bog if it's too retarded, but not necessarily cause the bog.
You are correct Greggie in suggesting the accelerator pump as the first place to look. I don't think a power valve would cause the "off the line" problem Robbie is describing. But I have been wrong before.....

 

[Robbiebaer]

It is the stock 2 barrel.

 

[Robbiebaer]

How would I fix the accelerator pump?

 

[greggieatthebat]

Hmm if it's stock then the accelerator pump probably isn't the problem. Some people have problems if they have installed an aftermarket Holley 4v (which are set up at the factory for mildly warmed up C***y 350s). I guess I'll have to defer to the other (many) experts on this forum, sorry!

 

[Royce Peterson]

Loosen the distributor bolt. Turn the distributor 1/16th turn clockwise. Tighten the bolt. Go drive the car. Let us know if this fixes it.