Slow then fast Idle?

[fisch]

I took my 521 for a 10 mi round trip drive to the post office today. (furthest I've gotten!)

 

I just put a manual choke weber on my l-16 and I am still running points. (I know, I have everything for EI, but I wanted to enjoy just driving it for a sec before I dug any more.)

 

When i started it up the idle was quiet low and smooth. I let it warm up for a good 10 min that way.

 

Once I started my trip though, when the truck wasn't moving the idle was alot faster than in the driveway. Not crazy reving or anything, just a consistant fast idle. I'd gas the pedal to see if I could knock it down, but nope.

 

Why would this happen? I've tugged on the throtle cable/linkage on the carb (while running) to see if it was sticking, but it seemed fine, and didn't change the speed.

 

Also it diesled once on shutoff, but did konk itself out. No backfireing. Other than that once, when I turn off the key it just sputters for a split fraction miniscule second and stops fine.

 

Thanks guys!

[]2eDeYe]

How's your throttle return spring?

[fisch]

2eDeYe;59802'']How's your throttle return spring?

 

I wondered about that, but when I pushed it with my finger to see if it would realease more, it didn't budge or change the idle speed.

[hang_510]

idle adjusted when at OT?

[]2eDeYe]

Fisch, small hijack...check the management discussion's latest thread. ;)

 

Does the cam rest against the idle screw or is there a gap?

[fisch]

2eDeYe;59806']Fisch' date=' small hijack...check the management discussion's latest thread. ;)

 

Does the cam rest against the idle screw or is there a gap?[/quote']

 

I thought it was at OT when i adjusted it, but i can't quite remember.

 

There is NO gap before the idle screw touches the lever thing it touches (is that the cam?). I thought I had left a little gap but looking now, nope

 

This could explaine it right? I wonder what turning it out will do for my already low starting idle.

 

Thanks for taking the time to check the baby steps here fellows. Trust me I need them. But the good news is once I learn something I rarely forget it!

[fisch]

Ahh i just checked teh instructions I got on line.

 

It said to back out the screw till it doesn't touch the lever, then turn in till it just makes contact, then from that position turn it in one full turn.

 

That is what I did, but I need to adjust from that point I am reading. After adjusting the mixture screw a bit.

[]2eDeYe]

Ya the initial settings are a baseline. The settings will vary depending on your local environment (altitude, barometric pressure and that sort of air pressure related stuff).

[fisch]

Cool I did my best to reset it, and set it when I am sure it is warmed up enough. (Temp gague doesn't work so I kinda have to guess.)

 

I will see what happens on the next cold start!

 

Thanks guys!

[hang_510]

I will see what happens on the next cold start!

this should be all till its warm...

I just put a manual choke...

[datsun dreamer]

This is frustrating! My weber does the same thing:(, But, I can actualy hit the accelerater and sometimes it will drop down:). I've rebuilt my Carb. 2 times and its still the same:confused:. Ive been told told it's the choke by numerous mechanics but havent actualy had the choke looked at. If you find the problem.....Please post:D I'm sure we are not the only guy's here with this sort of Carb/choke issues!

[DISLEXICDIME]

sometimes the floats get stuck and it will do this. smack the top of the carb and see if it go's a way

[ggzilla]

A vacuum leak can cause two symptoms:

- high idle

- dieseling instead of shutting off

 

The trouble with carbs is every little part affects every other little part. It's too hard to work on. EFI is much easier.

[racerx]

have you checked your timing, which causes high rpm and dieseling. As far as the float is concerned you can check your float level.

 

I've attached a float level set-up:

 

http://www.piercemanifolds.com/Float_Level_1.htm

 

But start diagnosing with the easy things first:

 

1). base setting both air/fuel and idle(rpm)

 

2). check for vacuum leaks, specially around the base of the carb. webers are good but them 2 mounting plates are horrendous when it comes to leaks- spray some carb cleaner around carb, intake, base and hoses. Do this when car is at operating temp.

 

3). Check for throttle play - shaft, after awhile they tend to lose it's tightness and believe it or not they are not built with bushings, which they should. So people will rebuild and put bushings.

 

4). 10 minutes to warm up your car is too much time, wasting gas. 3 minutes is more than enough....check your choke flaps when you disengae the choke, maybe your choke wire is binding some..They tend to do this when you tighthen too much on the first screw, snug is okay....when you pull on your choke it should be easy not hard.

 

Anyway keep us updated...