carbs 101

[Mikez73]

The 280zx distributor I bought back in December is apparent defective. I've reinstalled my points distributor until I can get another 280zx distributor.

I'm having a little trouble getting it to run again. The car is trying to start but won't quite run. I marked the plates before I removed the dizzy but I'm sure the timing is going to be a little off. I got one small backfire but I'm a little worried about have a bigger one because the (Weber) carbs leak a little bit.

My question is really basic. When the float chamber fills up doesn't the float close a valve to shut off fuel to the carb?

What I'm getting at is the fuel supply is supposed to be cut off when the chamber is full but I'm getting fuel out of the horns on the rearmost carb.

The fuel pressure is almost 8psi, would that be enough to overcome the valve and allow more fuel in?

[Travel'n Man]

Mike-

Depending on your carbs (rounds or flats - I do not have knowldege of flat tops) it sounds like the float bowl needle valve is not closing properly in the float bowl of that carb allowing fuel to continue to run over the level that is set by the float - or - your float is out of adjustment allowing too much fuel into the carb and it is running over - I would start with the valve, inspect and clean - or - replace. Once you break open your float bowl cover I would recommend to go ahead and replace the gasket for the lid - once you remove it, it will look like a Pringle potato chip - Bruce with Z Therapy can assist with your needs and he one of our members and sponsers. There are two excellent CD's that they offer and can give a great basic knowledge of how these carbs work and how to correct different issues - these are a must have for your proper set up and reference.

I just re-read the post and saw Webers - sorry - no knowledge of Webers - have you searched the site?

http://www.ztherapy.com/

Edited April 24, 2010 by Travel'n Man

[d240zx2]

Webers (and Mikunis) only require 3 - 6 psi. Running at 8, you're likely overpowering the float's ability to seat the valve.

[Mikez73]

Mike-

Depending on your carbs (rounds or flats - I do not have knowldege of flat tops) it sounds like the float bowl needle valve is not closing properly in the float bowl of that carb allowing fuel to continue to run over the level that is set by the float - or - your float is out of adjustment allowing too much fuel into the carb and it is running over - I would start with the valve' date=' inspect and clean - or - replace. Once you break open your float bowl cover I would recommend to go ahead and replace the gasket for the lid - once you remove it, it will look like a Pringle potato chip - Bruce with Z Therapy can assist with your needs and he one of our members and sponsers. There are two excellent CD's that they offer and can give a great basic knowledge of how these carbs work and how to correct different issues - these are a must have for your proper set up and reference.

I just re-read the post and saw Webers - sorry - no knowledge of Webers - have you searched the site?

[url']http://www.ztherapy.com/

Thanks Travel'n Man, the Weber was easy to miss and I appreciate the answer. Very nice looking car by the way.

Webers (and Mikunis) only require 3 - 6 psi. Running at 8, you're likely overpowering the float's ability to seat the valve.

d240zx2...thanks, that's what I'm thinking. I installed a cheapy Holley FPR but I can't set the fuel pressure until the car is running. The carbs probably could use new gaskets and seals too. Hopefully it doesn't catch fire before I can get the ignition timing and fuel pressure set