weber carb throttle body

[L18_510]

i have a 510 71 with a L18 weber carb. my car is burning to rich. somethimes when i shut the car off after ive been driving. it chokes and motors stays on for 5 to 10 seconds. then it shuts off. leving smoke coming out of the carb.. some can help me with this issue itll be great thanks.. also when i gas my throttle body shut off vaule doesnt close. i think im missing a spring or sumthing..

[jefe de jefes]

http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm

 

Is your timing dead on?

[L18_510]

http://www.redlinewe..._lean_best_.htm

 

Is your timing dead on?

 

ive been considering that my timing might not be dead on. one of my buddy mention it to me too...????????????

[banzai510(hainz)]

Its common for a open chamber head to diesel(run on) when a Weber DGV is installed. later Datsuns had a 12volt wire that went to a anti esiling selenoid. Most Webers dont have these except the 32/36 DGEV-IC.

My Datsun 521 desiels all the time. How I cope with it is when you shut the key off and the motor fells like its almost stopped then hit the gas pedal a little and hopefully it will loose vacuum and stop. Try it.

 

the mixture you can do your self. turn the screw IN/OUT till it runs smooth(the brass screw at base of carb with the tension spring on there.

 

as for the throttle plate closing?

The Weber will have a spring its self but the car should have a soft returns spring also that attaches to the 510 sheeps hook at the end. Make sure its a soft spring just enough to return it .

remember the is a speed screw also that needs adjustment for the idle speed.

do this in combo of the timming light(say 8-12deg)

mixture screw.

 

also make sure the 2nd barrel has a spring to keep that barrel closed. its in back of the carb

[datsunaholic]

Soft spring? Geez, I've put old Brake shoe return springs there (no, not the main spring, but the smaller lower spring). I've had too many experiences with stuck throttles. I've also re-wound the stock coil spring on the Weber another 1-2 turns to get more return action. When I lift, I want the throttle to slam shut.

[MicroMachinery]

I've read that the stiffer the spring you use, the faster you'll develop slop and play in the throttle shaft. Seems to make sense; I say you should use a spring that will get the job done, but not be overkill and cause premature wear.

[datsunaholic]

That is true. Which is why I rewound the coil spring on the front, since that doesn't have that issue. But I still use a relatively strong spring on the cable lever.

 

Now, on a 510 that uses a totally different setup, you can load the return all you want if you do it at the firewall.

[Shonuff]

i dont like having the spring mounted to anything but the motor.

 

when the eng twist's it'll hit the gas for ya, when i first put my side draft on my celica, i could lay rubber only using the clutch pedal, took me a while to figure out that it was the spring/eng rotation doing it.

 

 

+2 on big return springs.

[datsunaholic]

The 510s have a somewhat weird system where the throttle linkage pivot is on the firewall, so engine "twist" would work against you there.

 

However, if the spring is pulling the throttle closed, all the body/engine twist in the world won't open the throttle unless you twist enough to invert the positions. At that point I'd be looking at broken frames and torn sheetmetal. What it can do is de-tension the spring and let the throttle "float" open. That's one reason you want 2 springs, and both alone need to be enough to close the throttle.

 

Now, having the throttle cable shroud secured to the body (and not the engine) is a bad thing... that'll pull the thing open in a heartbeat. 510s don't have cables like that though.

[Shonuff]

my bad, i should of disclaimed that that was on a 20r, the carb is on the other side (passenger) of the motor from a L series.