vacuum advance question

I have a question since we are on the Vacuum Advance subject. I just got a '76 cj5 304, it's the first one those I've owned (extremely excited). Here's the question: where should my vacuum line from the distributer connect? my service manual shows it connecting to a "spark cto" which I do not have. I have a Motorcraft 2100 carb. Should I connect it at the intake manifold vacuum where all the spark cto and lines connect even though I don't have the spark cto w/ the 3 ports. Or, should I connect the vacuum advance to the "spark" port located on left side of the carb?

 

Heh. Bad timing.

You could move my reply too ...

 

Tim,
Where does the spark cto connect to the engine? I see in the service manual where all the vacuum lines go, I just don't see how the spark cto connects to the engine. Also, I have one other issue I'd like to run by you if you don't mind. My engine will just all of a sudden stall, not at the same time. If it sits at idle long enough, it just cuts off, no spuddering, just dies. And it also seems to do it randomly when you are up at higher spead (low rpm). Could the carb be running rich, and I just need to do a rebuild kit on it? Any and all help is appreciated.

 

There's a spark CTO and an EGR CTO. The spark CTO screws into the water outlet aka thermostat housing. The EGR CTO screws into the manifold next to the coil.

Which service manual do you have? You want the Jeep factory manual. There's a (mostly complete) '76 manual at www.oljeep.com

If the engine stops, like you turned off the key, and then runs again later, this seems more like an ignition problem. If you have the original Prestolite electronic ignition, these were (are) notorious for this behavior. You could replace the module, or the reluctor coil (pickup) in the distributor. Clean all the connectors and the reluctor coil mounting very well, and put it back together. You might get lucky and it'll work ok for a while.

The Prestolite stuff is most easily identified by the plastic vacuum advance canister on the distributor.

The Prestolite ignition system is, well, don't spend a lot of money on the Prestolite stuff. there are lots of options that are cheaper to fix and more reliable. You can go backwards to points ignition, or easily upgrade to the GM HEI system (aftermarket) or Ford Duraspark used in Jeeps from 1978 on. There are lots of possibilities for a system put together from junkyard and/or parts store pieces that will work a lot better than the Prestolite junk.

If you consider replacing the ignition, search on here for posts by member "Team Rush" or Google for his handles "Team Rush" and "Junkyard Genius". He has a lot of good advice about upgrades and understands the issues very well.