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Dealing w/ the Weber Fast Idle Adjustment Screw!


flipper

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I'm talking about the damn-near-invisible screw just to the right and kinda under the electric choke on my DGEV 32/36 Weber Carb. I finally found it and saw it clearly today for the first time ever, by using a flashlight in a dark garage. That made all the different. Man, is that thing hidden!

Anyway, I've been trying to figure out how to adjust it by reading here and from Redline's instructions and I think I understand what to do but I thought I'd write it down here to clarify it in my own pea brain and to see if you guys can set me straight if I've got it wrong.

Basically, there are two methods, the hot method and the cold method.

1/ Cold: With the car cold, and the key on but the car not started [DGEV only], hit the throttle once to close the butterfly plates. Look at the screw's position against the cam and screw the screw in or out depending on whether you want to raise the RMPs or lower them. Go drive. See what the change has wrought. Rinse and repeat til satisfied.

2/ Hot (as a continuation of above or as a first step). This is the Redline method. Warm up the car, turn it off, open the throttle and manually engage the butterflies to close them. Let go of the throttle and they should stay closed. Look at the screw. It should be touching the cam. Turn on the engine. Do not blip the throttle or it will disengage the butterflies. Go back to screw, turn in to increase speed, out to decrease.

If I've got it right, it seems to me both methods are accomplishing the same thing. The advantage to the hot method is you can hear the rpms going up and down. the disadvantage to the hot method is, the way that screw is hidden, you're likely to burn yourself trying to get at it. Or at least I am.

So, what do you think? Have I finally gotten this through my thick skull?

Whew!

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only do that HI IDLE adjustment COLD

during the first 5-min. of cold start / warm up.

should be 1600 - 2200 rpm when on the highest step

'86 R65 650cc #6128390 22,000m
'64 R27 250cc #383851 18,000m
'11 FORD Transit #T058971 28,000m "Truckette"
'13 500 ABARTH #DT600282 6,666m "TAZIO"

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eh. yeah, you have the idea.

Frankly, the best advice is futz with it until you're happy

with the way it warms up.

When you add the 'how much do I preload the bimetallic spring?'

question to the

'where does that screw want to be?'

question you start to approach madness.

And it's dependant upon your climate! We're often really damp,

so I find Jenn's car (mine's manual) wants a bit more than makes sense.

But that's what works, and she'd rather have too much choke

than too little.

I'd rather have too little, and double- pump it off the light.

Yes, now that you've found it, you can play with it until you

get bored!

heh

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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thanks, guys.

uh, madness has already set in; now i'm just trying to dial it down. i mean, i don't even if the fast idle adj screw is what i need to be dealing with, given my particular Weber issues, but i think I'll have fun finding out!

More questions later. Of course.

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one of the things that really screwed me up-

if you're talking about the screw that rides on the

fast idle cam, it wears. And it wears at an angle.

So that if you turn it a quarter turn, all of a sudden, you

get a lot more than a quarter turn of adjustment.

What that screw does is it sets the amount of throttle the

choke gets to add to the choking effect of the 'strangler' plate

in the top of the carb. So you both cut the airflow AND add fuel.

The screw pushes against the ramp that sets the taper,

and lets you add 'more or less taper'.

Gawd, that makes no sense.

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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