Factory Carb Problems

[rob020]

Hey guys,

in the last couple of months ive diagnosed way to many carby problems for
my mates in real life, and i thought this might make a good faq topic

if your car feels really slow, or recently youve lost alot of acceleration check
the vacuum diaphragm which opens the secondary throttle plate, its on the
corner of the carby closet to the firewall and the rocker cover and it looks
exactly like the one on your dizzy, unplug the vacuum line and connect a short
length and blow into it (if you suck and it leaks youll get shit in your mouth)
it should hold pressure, not leak.. if you can hear it leak or you have to keep
blowing that means its buggered and your only running on the first throttle plate,
as well as having a vacuum leak

also if your car will run for a minute and then stall, or only runs/runs well at low
engine speeds more than likely your fuel cut solenoid on the passenger side of
the carby is disconnected, there should be a loose wire somewhere in the vicinity
that gets 12v+ when the ignitions on.. if it IS connected, more than likely the
solenoid is busted (if you rule out other causes for your problem) if you remove
it and ground out the body and apply 12v to the wire the plunger tip should retract
towards the body.. you can either replace the fuel cut solenoid, or you can cut the
plunger off, but thats abit dodgey

cheers,
rob

[gmhighflow]

That good info rob020. If I could add about my factory carbies on my '81 scorpions 2,6 astron. I've had two of them do the same thing.The accelerator jet gets blocked and after trying to unblock it I gave up even after stripping it down.It must be a common thing with these carbies. i'm going to put another carby on from a magna and see if that stays good. Hope this isn't steeling your thread but it sounds good to have a diagnosis thread of factory carbies.

[gmhighflow]

Hey guys,



if your car feels really slow, or recently youve lost alot of acceleration check
the vacuum diaphragm which opens the secondary throttle plate, its on the
corner of the carby closet to the firewall and the rocker cover and it looks
exactly like the one on your dizzy, unplug the vacuum line and connect a short
length and blow into it (if you suck and it leaks youll get shit in your mouth)
it should hold pressure, not leak.. if you can hear it leak or you have to keep
blowing that means its buggered and your only running on the first throttle plate,
as well as having a vacuum leak

I've had this happen to mine also and couldn't be bothered trying to source another vaccum diaphram,so I adapted a Holey one.I had to modify the mount a little but fitted pretty good.Been running it for 12 years

[trainzkid88]

fuel cut solenoids were notorious for failing on tritons as they used the same carbie as the sigma. mine would run on and not idle and drink fuel i solved all of these problems with a Webber.
worn throttle shaft also cause problems such as surging when above 1500 revs motor would surge to 2000 -22000 revs and drop back again put extra seals on the shafts solved it for a while but re-bushing would be best. factory carbs are also hard to get parts for unless you want second hand stuff out wrecking yards where you take pot luck. the dealers cant help you once its ten years old Mitsubishi remove the listings from their system after market stores aren't much help either.