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Rough idle on startup, 308 WB Caprice.

Condy 0

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Hi,
82 Caprice with the 308. Has become rough on startup , guessing it's while the auto choke is on. Black smoke from the exhaust and runs like a chaff cutter. Have to keep the throttle up to stop it from stalling. Then if it does stall , it will only start with the foot flat to the floor. I've hit the carby (Original Rochester) with Carb cleaner, but i fear that the carb my need an overhaul. I'm not mechanical enough to do it & hence hope there may be a simple fix. Any Ideas ?
 

VR38

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Yeah it may need a carby expert, the floats can go off on them and the accelerator pump can leak, sure sounds like overfuelling.
Can you pull the top off the air filter and see what the choke blade is doing from a cold start?
 

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Yeah it may need a carby expert, the floats can go off on them and the accelerator pump can leak, sure sounds like overfuelling.
Can you pull the top off the air filter and see what the choke blade is doing from a cold start?
Hi,
The choke blade is pretty much 99% closed. Should it close off that far ?
Finding a carby expert in this day & age is not easy. Any suggestions would be appreciated.
Cheers
Rob
 

VR38

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Sorry can't help with experts, your at the wrong end of the island...
The blade can be adjusted.
Does it pull open when the engine warms up?
 

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Sorry for the late reply , have been away at work. Yes it seems to be completely shut (front blade) when cold and does open up once the motor warms up and hence it runs fine. Can i adjust the blade so it is not fully closed on start up. If i pull the blade open manually , the motor runs smoother but the idle does start to speed up a bit. Or is it just best to send the carby off for a rebuild in the long run?
 

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Carburetors with automatic chokes are now a rare animal due to them being an almost extinct breed, but they can be tamed easily, with a bit of TLC..
Get yourself a Gregorys manual for a Holden V8 of the right vintage. You may have to scour the Googlenet or a used book store.
Well worth it to able to DIY rebuild...

Edit .......... https://au.haynes.com/products/hold...gregorys-repair-manual?variant=48580010639553
 
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VR38

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Yes it can be adjusted, bit hard to explain, and must be done cold, once the motor has some heat into it, it throws you off.
Maybe google or utube your friend here.
 

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Sorry for the late reply , have been away at work. Yes it seems to be completely shut (front blade) when cold and does open up once the motor warms up and hence it runs fine. Can i adjust the blade so it is not fully closed on start up. If i pull the blade open manually , the motor runs smoother but the idle does start to speed up a bit. Or is it just best to send the carby off for a rebuild in the long run?
I’d say pull the carby off and send it off to someone to rebuild it would be your best bet as to who you’d send it to I’m in New Zealand so don’t know but I’m sure youd be able to find out thru someone on here or a google search, surely there’d be someone in Perth that knows there way around Carby‘s
 

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Pull the carby off, strip it down and give it a kit and do a setup yourself, google is your friend.

It's not rocket science, and it will be rewarding to find out how a carby setup works for your particular engine.

If the engine has a bigger than stock cam the butterflies will need to be adjusted to suit, and these things are best done before he carby is install.

The setup is the key and reasonably simple if you know the specs.

The fine tuning once installed can be a bit harder for a beginner, but you'd get it running better than you think.

That's my advice, learn and have fun being hands on with the vehicle.




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Get yourself a Gregorys manual for a Holden V8 of the right vintage. You may have to scour the Googlenet or a used book store.
Well worth it to able to DIY rebuild...

Edit .......... https://au.haynes.com/products/hold...gregorys-repair-manual?variant=48580010639553
.. don't waste your heard earned on this, really is quite poor
when it comes to the XT5 blue motor Quadrajet (308 or253 version)

get the genuine factory manual for this (and the other engine bits like the engine and dizzy etc))
Fleabay, gumtree, Marketplace, used book stores as said ... they are around

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