i have replaced my fuel filter 3 times (it has not been dirty), replaced the carb, disabled the choke and drained the tank, but still the primaries on my car are buggered (even with different carbies and jets).
The car refuses to idle smoothly at even at all at times, the tacho needle jumps iraatically at part throttle except when the seccondaries are open at wot.
I have sought help from my mecahnic and its got him puzzled. it started doing this once i started using the choke on one of the carbies about 3 months ago. I feels like it has altered the timming. The timming appears to be fine, as do the plugs. I feel its a fuel problem (was fine till i used the choke) but even on a different carbie it still is doing it. Any suggestions?
Its a 1200 ute with a 4 speed and a stock 1200 rebuilt last year.

Is the float level ok?? intake gasket got any leaks?

Chris

only thing not changed is fuel line, this could be blocked at one of the flanges or something????????????

my mechanic pulled a little plastic ball out of one of my brake lines once that was sitting nicely in the end of one of the back lines leading off the t-piece on the diff, buggered if we know what it was or how the bloody hell it got there!

If the tacho needle is jumping around like that it would suggest to me that your problem is actually electical. Check out all the low tension side of your electricals, points, coil, condensor, ignition switch, wiring, even the tacho itself.

I reckon Niscoupe is right, the problem sounds electrical. But my guess is a worn dissy bush. Pull off the dissy cap and check the shaft for excessive 'play'.

that is exactly what my ute is doing now! do you have extractors at all?

my problem is jets, the ilde, primary and secondary.

my tacho pings like goes up to 1000rpm then back to 800rpm and so on. My problem is fuel problem, not getting enough since extractors

I guess I could be wrong, but I can't see how more efficient exhaust scavenging could effect your mixtures.
Unless...check for vacuum leaks around the manifold gasket and make sure all manifold nuts are tight. Also check all vacuum hoses

If the idle goes quickly up and down (and the tacho just follows that) I'd say it's probably a fuel problem.

But, If the tacho needle jumps "erratically" (independent of the idle speed), this is an electrical problem. The condensor in the point set may be bad.

The odd part is that it you say it's OK at WOT ... if this is also higher RPM, it could still be electrical ... like if the shaft is worn.

If you still have the stock carb make sure that Anti-diesleing solenoid is opening when the ignition is on.
You might have a fat vacuum leak. If it runs ok with the secondary open(low vacuum condition) and not at idle/part-throttle(high vacuum)

okay, replaced the points and reset timing again today, it now idles, but if i touch the choke, it all stuffs up again.
The carby jets are fine (so my mech tells me) and there are no inlet or fuel leaks anywhere.
I may pick up another dizzy from the wreckers next week (when i get a day off), even though the mechaninc says there is no noticable play in the shaft or the disc, but i am now thinking that the spark leads may need replacing (a long shot prehaps).
There are no crushed or blocked fuel lines as fuel pressure is fine all the way to the carb (checked that one when replacing the fuel pump).
The idle now sits between 800 and 1000 rpm, usually fluttering around 1000 a some times dropping to 800. At least it idles.
Any more suggestions?