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Posted by: kenschipper Jul 25 2006, 09:36 PM

I have a completely stock 914-6 - weber carbs. When the engine is cold the car idles about 900 RPM. As it heats up the idle speed increases until it is idlying at about 1700 RPM when fully warmed up. It starts and runs fine. Just the high idle. Ambient temperature is currently around 85 degrees.

Since it is temperature related I'm currently thinking mabye a vacuum leak...loose manifold bolt. Any ideas on this one?

Ken Schipper

Posted by: racerx9146 Jul 25 2006, 10:30 PM

mine does the same thing but more like 1400, sometimes comes down by itself. I know the advance on these car is really touchy so if your idle goes up and timing kicks in it goes up even more, its a fine line. I do wish a weber expert could comment.

John

Posted by: ZZZZZ Jul 25 2006, 10:36 PM

Do you use the fast idle handle when cold? It's that handle next to the gear shift.....

If you don't....my guess is that the idle is set to high for warm running and it needs to be turned down.....cold starts, pull up on the handle...when warm push down.

It's also a poorman's cruise control.

Triple Webers do not have an electric or manual choke....just that fast idle thingy....

Posted by: racerx9146 Jul 25 2006, 10:39 PM

yup i never use the handle, figured it aint cold enough in Sacramento, CA. But you may be on to something. I will give it a try....
thanks John

Posted by: ZZZZZ Jul 25 2006, 10:42 PM

YOU have a conversion....unless you or the builder added it....most don't....you MAY be pulling up on the heater lever....

Posted by: grasshopper Jul 25 2006, 10:43 PM

QUOTE(ZZZZZ @ Jul 25 2006, 08:36 PM)

Posted by: racerx9146 Jul 25 2006, 10:45 PM

I AM aware i have a conversion give me a little credit. I built myself and i added hand throttle along with every part a 6 has... i even added the vacuum switch that hold the throttle open on decel but it never worked well.

Posted by: kenschipper Jul 25 2006, 11:37 PM

QUOTE(ZZZZZ @ Jul 25 2006, 09:36 PM)

Posted by: lapuwali Jul 26 2006, 12:03 AM

There's one throttle stop screw on each carb (not one on each throat). I agree with Mike that it sounds like the car is set up to idle too fast, so it idles cold without having to use your foot or the hand throttle to keep it going until it warms up some.

Also, the ignition timing may be advanced too much. It doesn't take much extra timing at all (2-3 degrees) to get the engine to tach up, which then advances the ignition even more, which causes it to tach up even more, etc. There's a fine balance point that has to be struck between using the throttle stop screws and setting idle ignition timing to get a good warm idle with carbs. Set this with the engine fully warmed up (drive it for at least 20 min, and try to get some freeway time in there), then use the hand throttle or your foot to keep it idling after a cold start.

Sacramento gets plenty cold enough to worry about cold starts. "Cold" doesn't refer so much to ambient temp, but engine temp. For something that normally runs at 190-200dF, 70dF is pretty cold. On a hot day, it doesn't take long for it to warm up after a "cold" start, often no more than 60-90 seconds, so it will idle on its own. On a cooler morning, it may take 3-4 minutes.

Posted by: Gint Jul 26 2006, 07:08 AM

That is also one of the typical symptoms of IDA's that have sloppy/worn throttle shafts. It creates a small vacuum leak that can change based on hot/cold temps. Jiggle the ends of your throttle plate shafts where they come out of each end of the carb body and check for play and/or change in idle.

Posted by: North Bay 914 Jul 26 2006, 11:06 AM

QUOTE(ZZZZZ @ Jul 25 2006, 09:42 PM)

YOU have a conversion....unless you or the builder added it....most don't....you MAY be pulling up on the heater lever....

Posted by: turboman808 Jul 26 2006, 11:49 AM

Mines the same way

I can't find a computer old enough to run the haltech softeware so I can turn the cold start feature on.