Erractic 3F carby idle

[Hulsty]

Has anyone experienced an erractic idle with a 3F carby motor and fixed the problem? My car intermittently on both petrol and has has a hugely erratic idle. Normal idle is around 800rpm, but today to keep the car from stalling at the lights I had to apply the choke and the idle was quickly jumping around from 400rpm all the way upto ~1500rpm. Take off from lights remove chock and all is fine, next set of lights and it idles normally.

This problem seems to come and go every few months but I have not been able to track it down. I was thinking its possible something to do with the vacuum secondaries on the stock carby?

 

[Clint79]

My brother had the same problem in his 3f 73 but does not have gas (lpg) it was a little elec idle sensor at the back of the carby that caked it a mate with a early std 3f 80 series lent us his sensor to test and it was the prob i can ask him tomorrow which one it was

 

[Hulsty]

awesome didnt even know there was one of those sensor things. Might see if I can get one through repco cheap enough to replace

 

[roscoFJ73]

Hulsty,when my carb on the 3F played up ,it was the vacuum secondary on the front of the carb. I had the lot rebuilt ,but I think the bellows can be replaced on its own for about 40 bucks.

The symptoms were that it would fart around when the secondary was trying to cut in ,usually as I was going round a corner or midway through an intersection changing gears,it had no idling problems that I recall.

Im guessing you need a kit put through your carb

 

[Hulsty]

I've cracked open my manual, its an idle cut solenoid, which cuts the fuel supply when shutting the engine off. It doesnt control the idle.


Kit through the carb might be due, last one was about ~100,000km ago. Car doesnt fart around or anything on gas, but on petrol its abit of a pig. At lowish rpm you cannot flatten the pedal as it floods and offroad it hates side slopes or inclines on petrol. Going up a resonable incline the carb runs dry, which is probably a pump issue.

Might hunt down another unit to rebuild.