Midget 1500 idle problem

[boxfullofyertoys]

I was hoping someone might be able to help me out with this...

I've noticed the idle seems to creep up toward 1500rpm when I'm out driving. When she's cold, it idles around 1000 unless I adjust it down after she's running, and even then the idle creeps back up when I'm on the road...

Again, I've adjusted the idle on the carb, but it only creates problems when I go to fire up again when she's cold (the idle setting seems too low to get her to fire over easily). I feel like I can't find that perfect balance...

Any thoughts?

I recently put a new Weber DGV on it...could it be the mixture? Wrong jet size?

Thanks in advance!

 

[Monark192]

I suggest re-posting this in the Spridget forum here - plenty of friendly helpful Sprite and Midget folks there.

Edit: Guess it has been moved for you.

 

[tosoutherncars]

Hmm... It must be something that's changing as it warms up... Electric choke on the DGV?

Or... air leak around the intake manifold, that's changing size as everything warms up?

My money's on the choke. I've got exactly the same setup, and when warm it'll idle nicely at 1K, but it won't idle for the first 5 minutes when cold... and that's because I've got the choke disconnected. (lost a little C-clip.)

 

[SilentUnicorn]

I had a similar problem with my weber. It turned out to be the nut holding the bell crank on the butterfly shaft. the instructions say not to over tighten this nut or you may move the butterfly in the bore and cause problems. mine used to loosen a little bit every now and then causing the symptoms you describe.


mark

 

[boxfullofyertoys]

Hmm... It must be something that's changing as it warms up... Electric choke on the DGV?

Or... air leak around the intake manifold, that's changing size as everything warms up?

My money's on the choke. I've got exactly the same setup, and when warm it'll idle nicely at 1K, but it won't idle for the first 5 minutes when cold... and that's because I've got the choke disconnected. (lost a little C-clip.)

It's an elec choke...as of now she's not having any problems starting/idling when cold as long as the idle is set high enough (about 1000rpm or so). After driving her for a bit, I'll pull up to a red light and she's howling at like 1500rpm.

Are you saying that the idle is just flat out set too high for the "choke off" position and it should be kicked down to something much lower? (i.e take her out for a good spin and then pop the hood and turn it down to 900-1000rpm) How will I get her started once she's cold...the good old "accelerator to the floor, turn the key" method? I feel like the car would protest quite a bit if I set the idle that low and tried to start it, but I guess it's worth a shot...I'd rather have to fight a bit to get her started than have my car idling like a bat out of h*ll at a red light

 

[tosoutherncars]

That's pretty much what I'm suggesting! :laugh: But once you've got the idle adjusted 'hot', you should be able to adjust the choke so that it doesn't die when cold... I must admit, that's the step I haven't bothered to complete. I just sit in the car and feather the gas for a minute or two. Once underway, it wants to die unless given extra gas for the first minute or two, and then once it's warmed up, everything's fine.

 

[boxfullofyertoys]

Ok, what you've just said combined with some more detailed Weber tuning instructions I just found on the intarwebs, the lightbulb is finally coming on. The instructions I had received with the carb were...well...awful.

So it looks like I have some work to do tonight:
- Double check the mixture
- Reset the warm idle
- Set the fast idle (which I didn't even know existed!!)
- Go for a long ride

Thanks for the help! I'll let you know how things turn out!

 

[Midget78]

Dave, Just curious; did you run a PCV valve from the manifold to the Motor?

 

[recordsj]

I have a similar issue (running a weber 32/26 dgv on a 1500). I can warm the engine up (without driving it around it will idle 800-900 RPMs. But if I go for a drive and sit at a stoplight it will be idling at around 1500 RPMs. Maybe this is what is meant by fast idle speed? (in manuals will you typically see a spec for idle speed and fast idle speed)

 

[boxfullofyertoys]

Recordsj:
Take a look at the link I posted earlier...the diagram shows a lot. Basically (from what I can interpret), the idea is to set the choke and choke screw so that when it's cold the idle is higher than what you've set for the normal idle (when the car is warm). As the choke opens, the idle gradually reduces itself back to a normal idle. I'm honestly still having some problems getting it to work the way I want, but maybe I'm just being too picky for my own good

Midget78:
No PCV valve here. Just a breather line that goes from the valve cover to the base plate on the carb...

 

[boxfullofyertoys]

Argggh!

Ok, So I spent some more time in the garage tinking with the carb, and I can't seem to adjust the cold idle without affecting the choke. When I tighten the cold idle adjustment screw (the one behind the choke unit), the choke wants to open as well. When I back it off, I'm right back where I started with a good warm idle but no control on the cold. Adjusting the choke first and then trying to adjust the cold idle doesn't seem to help either...

Am I missing something? I took a look at the old DGV that I replaced, and it seems like the two anjustment points (cold idle and choke) operate independently of one another, which makes sense to me...

Argggh!

Any thoughts?