Blocked carb heat line

[Iceboat711]

I've just joined the forum and already have a question. I'm working on a 73 240z that was put in the inlaws garage since 1985 and hasn't run since. I did get the motor running after putting in a battery and hooking up a gas line to the pump from a gas can.

I removed the flat top carbs last night to rebuild them. While they were off I decided to clean up the engine compartment. When cleaning off the line that supplies hot water to the rear carb I noticed it was plugged. I tried to pick out the crud that was inside and it was bright yellow and soft like paint. Eventually after picking at the mess I realized that there was some wood also in the line. So I screwed a sheetrock screw into the plug and gave it a pull. Out came a yellow colored pencil thay had been jammed in the line.

Now my question is why would someone block off that line and does the car really need the heat to the carbs if it's only driven in warm weather? Also are those flat top carbs as bad as everyone says they are?

Edited October 3, 2009 by Iceboat711
didn't finish post

[Walter Moore]

People block off the carb heater lines because they are not needed if the car is ONLY driven in WARM weather, and like all hoses eventually the ones to the carbs rot and burst.

So after they start leaking naturally some owners will just block off the lines rather than buy the expensive molded hoses to replace them.

If you are only going to drive the car, or run the engine in warm weather I suppose they are not necessary. But then what passes for "warm" weather in CT (or Indiana) is different than Southern California or Texas. Personally, I bought the hoses and hooked them up.

As for the flat tops, I have never even seen them so I have no personal knowledge. Sblake01 has stated in the past that they can be made to work properly. But support for them is very lacking. Most people seem to scrap them and install round tops.

Good luck with your project.

[Iceboat711]

Thanks Walter,

I plan on checking the hoses and putting it all back together as it should be. I've replaced all the soft fuel lines and most of the vacuum lines. The carbs are all cleaned and reassembled and I'll be putting them back in tomorrow and see how it runs.

[vercingetorix]

Flat tops have some vapor lock issues perhaps the lines were blocked in an attempt to address that problem. If you can afford it I'd seriously consider replacing them with ZTherapy round tops.

My2c