dgav and autochoke idle/start problems

[cookie720]

Hey, i have a 2L OHC engine with a weber dgav (auto choke) . I cant set the idle speed properly to work with the water autochoke. im not sure how it works, Can someone explain this to me? I cant get the car to start and idle well. Ive tried when the engine is hot and cold, and i still cant manage to get my head around this.

I did get it to idle well once, it wasnt "slowing down" as it got hotter though, and once i pumped the accelerator it cut out, as though it wouldnt hold the "setting" the choke had.

All the jets are standard and there shouldn't be any modifications the from original

[Pazuzu]

The problem could be with any number of things, unfortunately.
As for how the auto water choke works, it's fairly simple. As the water running through the choke heats up with the warmth it's absorbed from the engine, then the bi- metal spring inside the choke housing expands. This coiled spring then gradually opens the choke. The hotter the water, the more the spring expands, the wider the choke is opened; so, if all is working well, by the time the engine & water are well and truly warmed up, the choke will be fully opened.
I believe there is a point at which the auto choke doesn't come into play, when the choke has been opened up enough (i.e. the engine's been running long enough & everything's at a decent operating temperature). From my understanding, the choke is to the carby what the started motor is to the engine; once they've fulfilled their initial function, they aren't required to run until the system is turned off & started again.
Are you sure it's the choke that's causing the grief? How long since the carburettor was dismantled & cleaned?

If you're sure it's the choke, you may want to dismantle the choke assembly & make sure the spring is still intact. Make sure there is water running through the choke housing. Do you have a service & repair manual handy? Because they'll have a full section on idle adjustments. If you encounter more grief, let me know. It will help get my mind off my own car troubles

[Engine Guy]

Originally Posted by Pazuzu

The problem could be with any number of things, unfortunately.
As for how the auto water choke works, it's fairly simple. As the water running through the choke heats up with the warmth it's absorbed from the engine, then the bi- metal spring inside the choke housing expands. This coiled spring then gradually opens the choke. The hotter the water, the more the spring expands, the wider the choke is opened; so, if all is working well, by the time the engine & water are well and truly warmed up, the choke will be fully opened.
I believe there is a point at which the auto choke doesn't come into play, when the choke has been opened up enough (i.e. the engine's been running long enough & everything's at a decent operating temperature). From my understanding, the choke is to the carby what the started motor is to the engine; once they've fulfilled their initial function, they aren't required to run until the system is turned off & started again.
Are you sure it's the choke that's causing the grief? How long since the carburettor was dismantled & cleaned?

If you're sure it's the choke, you may want to dismantle the choke assembly & make sure the spring is still intact. Make sure there is water running through the choke housing. Do you have a service & repair manual handy? Because they'll have a full section on idle adjustments. If you encounter more grief, let me know. It will help get my mind off my own car troubles

Yes the bi-metalic spring does 'move' the choke flaps...but there is also a linkage that operates a fast idle (in cold/choke mode) make sure that the stepper is correctly set... as there are 2 idle speed screws (1 on the main venturi and 1 on the choke assembly)

Although before attempting any carb adjustments you should ensure that all ignition settings (timing & dwell angle) are within tolerances...

Cheers
Engine Guy