Help a rookie with dual carb setup on a 260z??

[dougs280z]

I have recently purchased a 74 260z. It starts up and idles ok'ish, but when you give it a decent amount of gas, it starts to bog. I tried researching, but i have no idea what kind of carbs i have. Im a fuel injection guy and know nothing about carbs. i just want to get it running decent so i can sell it...... anyways, the carb closest to the firewall has a pin that bobs up and down as you give it gas. I dont think its supposed to do this. On the top of the carbs there is a plastic nut that says "hand tighten". This is where the pin is popping out of the middle. I really dont think its supposed to be like this, so i pushed it back in and taped it up to see if it ran better. It does run better, but still not right. i basically want to know if that pin is something i should leave to float, or leave it pushed in. I also want to know what carb setup i have and if there is a diagram/forum on how to tune it. Thanks!

Doug

[MrFancypants]

The plastic cap is the carb damper. It should have a thin rod attached to it with a brass cylinder on the end. You fill the carb piston with oil (10W30 recommended) and the damper stabilizes movement of the piston.

 

It sounds like your damper is broken if the pin is shooting out the top. Time to get a new one.

 

First you'll need to find out if you have flat or round top carbs. The 260 came stock with flat tops (junk) but they are commonly replaced for the better round top versions from earlier Z's. Check out www.ztherapy.com to read up on the SU carbs.

 

 

 

- Greg -

[dougs280z]

alright, that sounds like what im looking at. it is the flat top. Ill try to fill that up with oil and epoxy it shut. thanks for the info.

Doug