Carb problem on Olds 5L

I have an '85 with an Olds V8 5L, 4-barrel, automatic, 260,000 miles. It often sits for two to five days between uses.

A couple of weeks ago, it started running really rough until the engine warmed up.

This was a sudden problem, not something that progressively got worse -- one day it ran fine, the next (well, the next time I drove it), it was bad.

My first thought was that the choke was sticking, so I got a can of cleaner and sprayed down the carb and all linkages and made sure everything was working fine.

That didn't help.

Further investigation shows that the choke is working fine.

The engine is running very rough and stalling until the choke kicks off. Once the choke plate opens, she settles down and runs fine (except for an occassional hesitation at stop signs, which it never had before, either).

If I manually kick the choke off and start the car, she's a little weak until she warms up a bit, but then goes strong.

When I checked the vacuum, it was about 12 (very, very weak) until the choke kicked off, at which time it settled down to a nice strong 22.

I can't check the timing when it is cold, but when she's warmed up (and the choke is off), it's right on spec.

I'm out of ideas.

Any advice appreciated ... greatly appreciated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wildepad wrote:

the
Maybe your choke pull-off went bad or you didn't hose it down well enough. You describe a classic case. It almost has to be.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Um, no, at least I don't think so -- the choke seems to work: it closes with the first movement of the throttle cable and then opens when the engine warms up.

It's just that when the choke is closed, she runs so rough that it is sometimes hard to keep her running.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.