1961 Hot Start question.

[mjabbasi]

Now that the brake booster problem is (hopefully) behind me, I wanted to bring up this issue I have been having with my car for as long as i can remember. To put it simply:

Cold Engine: Pedal pressed 1-2 times, turn the key and the engine fires within 1 second, idles perfectly, runs, drives and curb idles quietly and smooth as silk, it couldn't be better.

Hot Engine: After driving and the engine has reached its normal operating temperature and the engine is turned off, if started again, whether its 5 mins, 30 mins or 1 hour later, the cranking before it fires is a good 5-6 seconds, a lot longer as opposed to when its cold.

Now whether this is a timing issue (set as per the manual) or a carb issue (carb was rebuilt last year but this extended hot cranking was the same before and after the rebuild) I don't know but I'll reiterate that once the engine starts and the car fast idles, drives and curb idles at stops, the engine is smooth as silk and almost imperceptible and I would definitely not want to touch anything that causes it to function otherwise but I would definitely like to know if there is a solution to this extended hot starting issue.

[Karl]

G'day,
First thing is "If it ain't broken, don't fix it"
Could be a million things. First impression would be because the choke is now turned off, the fuel mixture may be a bit lean. Or do you pump the accelerator prior to hot starting. If so maybe to rich. Do a test and see if you can make it better or worse by not using the accelerator and using lots of accelerator prior to a hot start.

Put a vacuum gauge on the manifold and see if there is a crook valve. A vacuum gauge can tell you a lot about a engine.
Just some thoughts.
Karl.

[mjabbasi]

Yes the choke system has been removed. When its hot I only press and hold down the gas pedal once, I don't pump it for fear of causing flooding.

[Aaron65]

Hard hot starting (heat soak) is a common problem with modern gasoline; all of my cars do the exact same thing as yours to some extent. There are ways around the problem (like running a return line to the fuel tank), but probably the easiest way is to find what starting method works best for your car. A well-known carburetor expert shared this with me on the phone once, and it works pretty well: Keep your foot off the gas and crank the engine for about a second. This clears out the fuel vapor that has collected in the cylinders. Then, slowly push the throttle to the floor and crank until it fires. Obviously, be ready to take your foot off the gas when it catches.

The problem is that modern gas expands at a lower temperature than it used to. When it overcomes the needle and seat, it drips onto the hot manifold, creating vapor that then floods the engine. It's pretty much a fact of life unless you switch to fuel injection.

Of course, you could have other problems (have you checked the points lately?), but it sounds like this is the most likely, if gas is the same where you live as it is where I live. Good luck!

[mjabbasi]

I'll definitely try this method you just mentioned. No Points in the car anymore, its got the Pertronix HDI Ignition system.

[RLZegers]

I have the same problem with my '63 ht. Do you think it might help to switch to a 160 degree thermostat from the 180 that's in it now?

Just a thought and thanks!

[RedBird64]

carbs often have problems with hot-soak, even with good "real" gas. If you use gas with enthanol it will boil at 173 degrees. It can easily get that hot under the hood after it shuts off - or even while it's running.

[mjabbasi]

While I have no issues with the Carb, would a replacement 'modern' Carb say something like Edelbrock etc solve this issue or would it be the same?

[stevegintn]

Moin Abbasi, sorry I cannot help you - the suggestions given above seem plausible?

Not trying to hijack your post, but I have the OPPOSITE problem with my 62 - if I don't run my engine for even overnite, it seems like the carb dries out?

I pump the accelerator several times, turn the key and it may hit once, but does not start. I end up having to "prime" the carb with a little gas.

Once it starts, runs to warm temp, all I have to do is just touch the key and it starts right back up (without touching the accelerator).

I have installed an electric choke, and it seems to be working properly (opens upon warming).

I am also wondering if it's time for an aftermarket carb?

[Aaron65]

If your carb is working properly, an Edelbrock will not help, as they are known for being prone to heat soak. In fact, Edelbrock sells a special gasket to insulate the carb from manifold heat. Don't get me wrong, I like Edelbrock/Carter carbs and have one on my Mustang, but it may not solve your problem.

You may have already done this, but you may want to check your float levels and your power valve. When I bought my '63 back in October, it was running very rich at idle, and I found that the power valve was not tight, so I assume fuel was somehow draining back into the manifold. I tightened it up and that problem was solved.

Of course, I now have the problem that Steve is having...the car starts hard cold. I still haven't gotten to messing around with that too much; it's definitely winter here in Michigan and the car isn't going anywhere for a while.

[stevegintn]

Aaron, please let me know if you solve your cold start question - although temperature is not the issue for me, here down south - I have the same hard cold start problem in warm temps, if as I said, it hasn't been run in a day or two? (which is why I suggested, the carb is somehow 'drying out').

[mjabbasi]

Oh that happens to me too! If I don't drive the car for over a week-10 days, I have to pump the gas pedal a few times and it will briefly catch for a second then go off, then I wait a few seconds and try again then it fires and holds. Now if I go back to the car the next day and start it, half a turn of the key is all that is required, even 3-4 days later, just half a turn and it fires, but anything more than 7-10 days, it requires a few pumps of the pedal and if its been a month or more then a bit of spray down the carb to shake things up, then it starts on the second, third attempt. Exact same case with my '62 Lincoln but even after a drive when the engine is hot the Lincoln starts within a second.

[stevegintn]

Oh that happens to me too! If I don't drive the car for over a week-10 days, I have to pump the gas pedal a few times and it will briefly catch for a second then go off, then I wait a few seconds and try again then it fires and holds. Now if I go back to the car the next day and start it, half a turn of the key is all that is required, even 3-4 days later, just half a turn and it fires, but anything more than 7-10 days, it requires a few pumps of the pedal and if its been a month or more then a bit of spray down the carb to shake things up, then it starts on the second, third attempt. Exact same case with my '62 Lincoln but even after a drive when the engine is hot the Lincoln starts within a second.

MJ, I was told on here, it's a weak or faulty power valve, which would require replacing (as part of a carb rebuild).

Has your carb been rebuilt? (mine was, less than 100 miles on it now)

[mjabbasi]

Yes it has been rebuilt, about 2 years ago and the car wasn't run much since then.

[RedBird64]

An Edelbrock carb wont help (BTDT) because modern fuel will boil at the temps seen in a closed engine compartment after shut down.
Unfortunately, there really isn't any good answer (except maybe EFI).

Scott