[bob9909]

Hi all, I know I am new here and that there are already loads of carby threads going around. But I have been lurking around reading heaps of them, but my issue is kind of similar but different as I assume it is something I have done wrong that is screwing it up.

She was running alright, would idle perfect and ran alright but lacked a bit of power when going, so I decided to rebuild the carby (I'm pretty inexperienced btw). Well, I got it stripped down cleaned and rebuilt (took about a week for me with lots of youtube vids and reading, I learned a lot but still don't know a lot of things), when I put it back in it wouldn't idle, so after messing with the idle speed adjust screw it was fine (I think now it was fine cos it was starting to warm up)

It runs great, feels like it has much more power than it did before, but when I go to start it when cold, it doesn't idle, runs lumpy and blows smoke, though once it is warmed up all of this goes away and it will idle nicely. I don't think it has anything to do with the idle speed screw as once it is warm that seems to work.

Could someone point me in the right direction as to what could be causing issue with the carby when starting cold but not when warm?

This is on a Suzuki sierra 95 model, it has the standard Aisan twin throat carby and it only has a one step idle actuator system if that helps.

Please help me :S
Like i said, it ran fine before and I haven't messed with anything I didn't need to to get it apart, and it runs perfect at speed, I just need to know what I have messed up making it not want to start when cold.

Thanks in advance
Cheers

[Microwire]

Sounds like a choke issue to me. For the lumpy and smoke part - have you checked your plugs? do they look alright etc?

Others will chime in soon with more knowledge but there's something for you to look at for now.

[bob9909]

Yea, the sparks look good, but I assume the actual problem probably doesn't last long enough to leave much of a mark as once it has warmed up a bit it starts to idle fine, no more smoke or rough idle.

[royce]

if its only when cold you need to adjsut the choke

when cold the flap should be shut, follow that linkage and youll see the little gear that actuates it, it has a line on it that should line up with the other side, to adjust this follow further down to teh lever that attaches to the housing with the water hoses going into it, undo the lock nut and turn the screw till they line up, it sounds like you might need less tension on the flap, this whole adjustment sets how long the choke stays on for in relation to coolant temp

next see how your fast idle speed is, if its low (1000-1200rpm might be good) the adjuster for that is upside down on the throttle linkage the accelerator cable wraps around, to set it you need to turn the engine off and open the throttle so the screw on the bottom is now accesable and turn it in a bit for more revs, out for less, start and try, repeat till its right.
Hard to do cause the more it runs the more the revs drop anyway so it might pay to have a shot, if its wrong leave it to cool again

[bob9909]

Thanks for the great and detailed reply, you have given me a couple of extra bits and pieces to work with. I actually think the flap needed more tension as it was pretty loose and wouldn't fully close by itself, but that hasn't helped up yet, will try experimenting a bit more with the fast idle.

Can you explain to me how the carby changes when it is warm? I think it would help me to understand it a little bit better, the fast idle screw controls the effect but how does the carby know the car is warm or cold? is there a sensor, or a mechanical linkage that adjusts according to temperature?

I think you have given me the bits that I need to adjust to make this work, I just need to keep experimenting with them. Thing is I never changed any of these when I pulled it apart :S

Another thing that I found and fixed was the linkage at the front that adjusts when the heater or lights are on needed to be adjusted as it wasn't making a difference when activated.

Thanks again for the help guys, I really appreciate it
Hope I can get this working again
Cheers

[royce]

the little cylinder that the coolant hoses attach to has a waxstat inside, works like a thermostat and makes the long threaded section sticking out of it move when it heats up and cools down, which then closes the choke flap and moves a cam on the throttle linkage to engage teh fast idle screw

You may find somebody has fiddled before and noe whatever else is right has made the choke seem funny

[bob9909]

Thanks for all that info Royce, I've got it working great now, took a bit of tinkering but I ended up loosening the choke and upping the fast idle and now she's starting first go

This looks like a great active forum with lots of knowledgeable people, I'll be sure to stick around and hopefully help out when I learn a bit more

Thanks again guys I really appreciate it

[SloSj70]

old thread but i really need some more info on it.. i have the same trouble with running rough when cold and was reading this thread before asking for help.. Royce mentions to line up the line on the white geared section with the other side.... im not sure which mark he means and whats meant to be on the other side... i can see a line on the white section.. actually i see two marks.. does anyone have a picture of the marks or lines he is talking about... thankyou..
brent