I noticed this issue at the end of last summer/fall, but it seems to be getting worse as I have begun driving for the season again. When I drive the car and get everything good and warmed up, if I shut the car off and get back into it and start it before it cools out, it starts really hard. Like it takes a good 15-20 minutes before it will start again to what I would call normal starting. 

I am wondering if this has something to do with the exhaust crossover tube? Is hard starting when warm a common issue when the valve in the intake manifold is stuck open allowing all exhaust gasses to pass under the carb? This would make sense to me, I am just curious what others think. 

I am thinking it is also probably time for a carb rebuild and complete ignition system overhaul. I'll gladly take some pointers on that process as well!

Also as an update, which I should include in its own post, I have "rattle can rebuilt" the new transmission I got from Jason (thanks again!). It cleaned and painted up really well! I did a few aspects of the trans in Cadillac Blue. Like the dipstick tube, transpan, and governor cover plate. I think it turned out sharp!

Anyhow, all for now, I look forward to hearing everyone's thoughts on the hot start and ignition system rebuild!


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Robb,  I will address ignition,  A 60 year old distributor needs more then a new set of points and condenser. advance springs lose tension over time, wiring gets hard & needs to be replaced , the factory lube for the upper bushing is depleted, stop bushing is gone they are just rubber and deteriorate.  It needs to be tested on a distributor machine to check the centrifugal advance & vacuum advance curves to see if it meets the factory data points @ different RPM. Cadillac used eight data points for centrifugal advance & eight for vacuum advance. there is also a cruse RPM spec which is a combination of centrifugal and vacuum advance measured @ 2500 RPM You need to do a ignition circuit resistance test , test the condenser, dwell variation test,  point spring tension test cam lobe accuracy test   also test your coil on a coil tester . it needs to be disassembled  the shaft polished the cam polished, bushings checked. all these thing i perform when i do distributor repair.  I would rebuild your carb also,  but all the tuning won't help if you don't have Good compression in all cylinders. 

Hi Logan,

     Read your post about the starting issue and running hot.  Does your Caddy still have a heat riser on the driver's side and is it possibly stuck in the closed position?  If you have one and it's almost always closed, then the hot exhaust gas will stay under the intake manifold as you presumed.  In addition, how is your internal choke tube inside the intake manifold?  The heat riser and internal tube work in tandem and will certainly affect the choke and starting.  We both live in cold climates and I'm always keeping an eye on the fast idle and kick down rpms.  Just a thought and hope this helps.

Yours truly,

Dennis DiBari, Cottekill, NY


The fast idle actually works. At least it did this winter. The few times I drove it before the salt hit the roads when it was 35-40 degrees or so, the fast idle worked really well and the car warmed up rather quickly

I think the heat riser is what I was illuding to in the original post. I believe some people pull the intake and block that port off and it, to my understanding, help the carb get up to operating temp in the colder climates. Thats all fine if this is a daily driver in the winter, however, I rarely drive it when the temp dips below 40 and the car is always warmed up before any hard driving. 

I believe the choke tube needs to stay intake as well, correct? This would facilitate with starting and the fast idle?

Thanks for the help-



     If the small hole in the intake manifold (the one that goes to the choke) is blocked off, then the internal choke tube is probably rusted and clogged.  If that is the case, then an external choke stove is needed to heat the choke to open.  That internal tube is designed to work with a healthy heat riser.  Any way to check if your riser is stuck open or closed?  If it is mostly closed and the internal choke tube is clogged, that is not ideal.  To replace that internal choke tube can be an arduous task, and the rusted tube must be machined out.  Hope this helps.

Dennis DiBari

It is certainly helpful! It seems I need to do some more research on my end before I go tearing into anything. 

Check everything out and see what is in place.  Best of luck with it.  Let me know what you find.

Dennis DiBari

Check the accelerator pump  on the carb. It should have strong squirts of fuel. 



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