I have a 1968 Cutlass with a 350 engine. I recently had the Rochester 4bbl rebuilt and the car runs fairly well. (aside from a less than smooth hot idle) After sitting off for 10-20 minutes hot, it takes a solid 5 seconds of cranking to get it started. I suspect the carb is getting heat soaked and expanding fuel is entering the intake. (not uncommon I suppose). Heat might have something to do with the hot rough idle also. I have already gone everywhere with regard to the idle issue, see other thread.

Sooooo, I am thinking about a heat shield at the base of the carburetor. Can anyone point me in the right direction as to buying one, or have any suggestions as to a better fix?

 

assuming percolation is the issue:
are you using a thin gasket for the carb. to manifold surface? by thin, i mean a gasket that is thinner than 1/32".
is the the car's cooling system in proper working order?
is the heat control valve in the exhaust manifold working properly?

other common possibilities:
floatl level in carb. set too high.
leaking needle/seat.
does the carb. have a bowl vent on the top, in front? is it adjusted properly?
fuel pump is of the proper pressure and type?

just a few quick thoughts,
bill

 

Check your local parts store. This is the item you are looking for.
http://www.jegs.com/p/Edelbrock/743639/10002/-1

 

Bill,

Yep, its a paper thin gasket, leading me to a heat shield or a spacer. All the components of the cooling system are new. Carb is professionally rebuilt, to include even the throttle bushings and well plugs. New stock fuel pump that was called for in the NAPA book. Heat valve works too. Thanks for the suggestions.

 

you should be using the thick gasket(1/8" to 3/16" thick). this is likely most/all of your problem. the carb. is able to absorb too much heat from the manifold. all you really need is the correct gasket.


bill

 

Actuall Bill , I misspoke, it is 3/16th or so, I was thinking of a different vehicle.