Rough cold starts, but then runs perfectly - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MacGyver72 · 10-25-2012, 07:37 PM

Yep. That's it.

trac209 · 10-25-2012, 07:41 PM

Yes that's the one,and it should move when you turn the choke housing.
Posted via Mobile Device

White70C20 · 10-25-2012, 08:06 PM

My truck has the same problem, plus it idles really low (almost sputtering) when its cold. I was told by PO that its a Holley carb.
Posted via Mobile Device

geezer#99 · 10-25-2012, 10:17 PM

You're missing enough parts on your choke that it'll never work right. SEcondary lockout, secondaries air valve pull off pot and linkages. If you get the choke plate to go shut to start it then it'll stay shut. Missing the choke pull off parts.
Here's a link with pics.
http://www.vetteprojects.com/kstyer/quadrajet.htm

MacGyver72 · 10-25-2012, 10:32 PM

Hell, I didn't even notice that. Great catch geezer. Been too long since I've done a rochester I guess. He's right. You'll never get it to function properly without the right parts.

*Mister-B* · 10-25-2012, 10:39 PM

Quote:

Originally Posted by geezer#99

You're missing enough parts on your choke that it'll never work right. SEcondary lockout, secondaries air valve pull off pot and linkages. If you get the choke plate to go shut to start it then it'll stay shut. Missing the choke pull off parts.
Here's a link with pics.
http://www.vetteprojects.com/kstyer/quadrajet.htm

I don't know guys. After further inspection and adjustment, it looks like the engine must have been too warm earlier when I worked on it. After letting it sit, I can see the flaps move when I adjust the choke. I can also tell there's spring tension when I move the flaps. So, I started over with the adjustment, and it runs like a dream. Fires right up, and it's night time and very cold right now. Went for a drive, and it runs great and idles perfect. You sure I'm missing parts?
Posted via Mobile Device

MacGyver72 · 10-25-2012, 10:46 PM

Yes you are but if it's running great, you didn't need them. LOL.

Glad you have it sorted out. One of the reasons I love these old trucks and chevy motors is that they are very forgiving if not perfect. You'll have performance issues but perhaps not noticable. I once had the mechanical timing weights in the distributor overlap each other and I drove it like that (running rough as hell) for about 10 miles before I got to a shop. When I started it to show the guy, he made a funny look, had me shut it off and pulled the distributor cap then the rotor. He showed it to me and said he couldn't believe the truck was running at all. A new (read junkyard) distributor and all fixed.

MacGyver72 · 10-25-2012, 10:48 PM

Actually those photos are of a heat riser choke and not an electric one. you can see where yours is converted so the pulloff may not be needed for the electric modification you have. At any rate, check to see that the butterfly valve is closed when cold then is open when warm. As long as that is happening, happy driving.

10-25-2012, 07:37 PM	#26
MacGyver72 Registered User Join Date: Sep 2011 Location: Greencastle, IN Posts: 132	Re: Rough cold starts, but then runs perfectly Yep. That's it.

10-25-2012, 07:41 PM	#27
trac209 Registered User Join Date: Dec 2011 Location: winnipeg Posts: 1,107	Re: Rough cold starts, but then runs perfectly Yes that's the one,and it should move when you turn the choke housing. Posted via Mobile Device

10-25-2012, 08:06 PM	#28
White70C20 Registered User Join Date: Oct 2012 Location: Kansas and Iowa Posts: 349	Re: Rough cold starts, but then runs perfectly My truck has the same problem, plus it idles really low (almost sputtering) when its cold. I was told by PO that its a Holley carb. Posted via Mobile Device __________________ White70C20 1970 Blue C20 - 250, 4 speed 1985 Ford Thunderbird 2005 Pontiac G6

10-25-2012, 10:17 PM	#29
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,736	Re: Rough cold starts, but then runs perfectly You're missing enough parts on your choke that it'll never work right. SEcondary lockout, secondaries air valve pull off pot and linkages. If you get the choke plate to go shut to start it then it'll stay shut. Missing the choke pull off parts. Here's a link with pics. http://www.vetteprojects.com/kstyer/quadrajet.htm

10-25-2012, 10:32 PM	#30
MacGyver72 Registered User Join Date: Sep 2011 Location: Greencastle, IN Posts: 132	Re: Rough cold starts, but then runs perfectly Hell, I didn't even notice that. Great catch geezer. Been too long since I've done a rochester I guess. He's right. You'll never get it to function properly without the right parts.

10-25-2012, 10:46 PM	#32
MacGyver72 Registered User Join Date: Sep 2011 Location: Greencastle, IN Posts: 132	Re: Rough cold starts, but then runs perfectly Yes you are but if it's running great, you didn't need them. LOL. Glad you have it sorted out. One of the reasons I love these old trucks and chevy motors is that they are very forgiving if not perfect. You'll have performance issues but perhaps not noticable. I once had the mechanical timing weights in the distributor overlap each other and I drove it like that (running rough as hell) for about 10 miles before I got to a shop. When I started it to show the guy, he made a funny look, had me shut it off and pulled the distributor cap then the rotor. He showed it to me and said he couldn't believe the truck was running at all. A new (read junkyard) distributor and all fixed.

10-25-2012, 10:48 PM	#33
MacGyver72 Registered User Join Date: Sep 2011 Location: Greencastle, IN Posts: 132	Re: Rough cold starts, but then runs perfectly Actually those photos are of a heat riser choke and not an electric one. you can see where yours is converted so the pulloff may not be needed for the electric modification you have. At any rate, check to see that the butterfly valve is closed when cold then is open when warm. As long as that is happening, happy driving.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.