Glad to hear the problem was found.

Btw, a new Weber 32/36 setup for L-series, runs perfectly fine on stock A12 to stock L20B. Not with optimum fuel economy, but will idle, accelerate and cruise without any noticeable problems. You still have to set the idle speed and idle mixture, but you don't have to change the jets.

heyy guys just letting you's know that there wasnt much even wrong i got my brother to look at it the other day and we noticed the choke butterflies on top of the carbies were seized for some reason so we fixed that and now its running like a dream again haha thanks for all the help..

The idle jet on the 32/36's are easy to get to. They are located on the side, there is a brass cover screw/holder covering the jet. Identify what you have currently installed. At a guess im going with 55 /60 being stamped on the jet. 40 /45 is probably more in the zone. An air /fuel ratio gauge would be the only real way of knowing if the mixture is on the money. U-ego make a cool digital one which uses a bosch wide band o2 sensor that needs to fitted to your exhaust, or pay for some dyno time. Maybe you mechanic has a gas analyser.

yehh still has standard cam yehh its idiling lumpy because the jets are to big i know that but im unsure of what jets to get..yeh im unsure about the bridge actually..naa not out of the carby coming out of the exhaust only when you are coming back down through the gears and its bad backfire to and real rumbly, its also hard to start and almost undriveable in first gear it will be good for a few seconds then just bog down then you have put the clutch it give it a rev then go again

Still has the standard camshaft? If so, it should not be idling lumpy, idle jet is too big [Idle jet also meters fuel for progression cct also]. jets are approx $6 - $10 online. Is the bridge still in the factory inlet manifold? the weber adaptor is mounted just on top. It is worth removing the bridge area to improve the flow characteristics. When you say backfire, do you mean the carb is coughing? unlike backfire out the exhaust. If so, it suggests a lean mixture condition is occuring, probably when the secondary throat throttle plate is opening, combined with no fuel.

The Carby has only done about 3000km so its basically new i bought it brand new from weber so yeh im just using the jets that i was supplied with im pretty sure there too big but i was going to leave them as im thinking of putting a cam in so yehh..The gasket was sucked in due to the backfiring apparently.. and i have electronic distributor which has been professionally fitted by a mechanic that knows what hes doing as hes been in the business for over 30 years and after all the recent mods it was tuned by the same mechanic running absolute perfect not even a misfire only abit lumpy on idle but no stalling..

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Weber hater ha ha. From a Weber liker, all carbs require an element of maintenance from time to time. I fail to see how a change in fuel octane can result in the gasket being deformed, I guess it's possible, I would sooner believe the gasket failure was a result of ethanol content though. Either way I would suggest the poor ecomomy is due to the faulty gasket, incorrect jet selection and maybe the timing is not set to optimum. Worth also checking the distributor internals for correct functionality, i.e bob weights on the mechanical advance, dwell angle on the points and the vacuum advance diaphram on the side of the distributor.

Lastly, to take advance of high octance fuel in NA applications, you need to up the cylinder compression ratio.

I've never had problems with my twin downdraft Webers except when I had a blowthrough SC setup. With the drawthrough they have been working great. I've been dumping huge amounts of fuel into the cylinders and my plugs still come up nice and clean. Stock Webers have 40's for both primary and secondary jets. I have two carbs and I run 210's in the primarys and 60's in the secondarys. I have gased my car up at the airport a few times with 104 octane with little or no results. No problems with the carbs. It just cost to much to run. I just stick with the 92 octane. Oh and the chokes, I yanked those out. They just restrict airflow.

yehh well i wont be going back to that fuel station anymore might stick to BP from now on. Ahk yehh i have heard a few stories about that octane booster my mate has a AE71 corolla and uses it all the time he reckons its great..

Up Hear in Qld A few Guys in a datsun club NEVER USE any fuel From Caltex
As do i Only Use BP 98. I would get around 280ks out of 30 liters
On a Stock A12. I recently started useing a octant boster with just 91.
on long drive,s that i have been doing i got almost 100ks more out of 30L
And the car runs better now