Carbs not getting vacuum

[Mtk]

Help please...   I just put new carbs on my car and they are not getting gas.   The fuel line to the carb dose have gas.  I don't think I’m drawing any vacuum.  Where do these to wires go.  Thanks for the help 

[Mark Maras]

Tell us the history of the carbs. Did anyone rebuild them? Not that I think they need it, just looking at a possible screw-up during assembly. If there is fuel in the carb. fuel lines, the banjo fittings on top of the float bowls contain a filter screen. Clean those and then verify your float fuel levels are correct.

[Mtk]

Brand new carbs from z therapy.  Doesn’t seem like fuel is going through the carb.  Do the two wires have anything to do with it?

[Mark Maras]

 The carbs have no elec. wires. I'd pull the float covers and take a look inside and take a measurement from the bowl top edge to the fuel level. If you've verified you have spark at the plugs, try spraying some starting fluid (ether) into the carbs and see if the engine starts and runs for a few seconds.

[Mtk]

Ok I will give that a try.   I does start fore a few seconds with starter fluid.   Thanks for the help 

[Mtk]

Would you have a link at exactly what I’m looking for when I remove the float covers 

[Mark Maras]

Search using the word "floats" and you'll find pics and discussion. You'll be looking for the depth of fuel in the float bowl. Measure form the top edge of the bowl down to the fuel level. Pics would be great. Also, while holding the cap and float assembly , with the floats hanging down, blow into the inlet tube. You should be able to blow air through it. Now slowly lift the float while blowing into the tube. When the float is lifted to about 9/16" from the bottom of the float cover, you shouldn't be able to blow through it. 

[Mtk]

Mark thanks for all the help.   I will give that a try this weekend 

[Randalla]

I ran into a similar problem recently on a car I purchased. Make sure none of your fuel hoses are too big for the metal lines they connect to. If they're not the proper size, it doesn't matter how tight you make the hose clamps you will not get good enough suction to fill your float bowls. They should be hard to push on. If they are not there is a pretty good chance they are too large a diameter.

[siteunseen]

When you pull the choke handle do the nozzles drop down? Those hoses from the float bowls to the nozzles seem to stick outward more than mine. Could they be pinched somehow?

[siteunseen]

Here's my favorite quick way to check the fuel level in the float bowls. I think that's 5/16 clear hose? I buy it at Lowes. 3/16" not 5/16. Sorry!

Edited September 8, 2020 by siteunseen

[Randalla]

siteunseen's approach is a good way to more precisely check float levels. I manufacture and sell Float-Sync on eBay (pictured below) and have received excellent feedback, if you are interested.

Float-Sync is the best way to calibrate float levels between two Datsun 240Z SU carburetors because you'll actually be able to see the fuel level in each bowl, even with the car running. The level of fuel in the float bowls is the first step you should take before making other fine adjustments to optimize “runability,” In my experience Float-Sync gets you to the baseline as quickly and accurately as possible.

I learned, like most of us, to set float levels by removing the float bowl cover and measure the distance between the edge of the lid and the top of the float while the cover is inverted. What I've since learned is just how imprecise this approach is because many variables. Those variables include whether the carbs are being run with or without float bowl gaskets, how many turns down the jet nozzles are set, if the float valve is fully opening and closing, if the float bowl lid has short or long ears and if floats are intact and their buoyancy is the same in each float bowl. I'm sure there are a number of others.