So when the engine is hot (example: I stop for gas), and go to start it up again, it takes a lot of cranking to get started. What gives? Is it the fuel system? Gas is definetly going into the carb (Rochester Q-Jet). I adjusted the bowl slightly to see if that would help. Pump works fine.

On top of that, last time this happened, it was cranking and cranking and I let off the key and it kept cranking! I checked my starter solenoid to see if it was stuck and it looked great (and is <1 year old) so I don't think that's the problem. Could it be my ignition? Wiring? Ground? Battery?

Thanks for any help you got!

Sounds like the classic "hot" start issue that has been discussed here more than I can remember. Do you have headers? What gauge battery cables are you running? What amp battery? Did it stop cranking by itself eventually, or did you have to pull a batt cable? That particular issue is probably a defective ignition switch...seen it before.

I'll have to check the amp and guage battery after work. To get it to stop, I had to pull the batt cable.

I'll look in the archives to see some past advice. What I would like to know is if there is a way I can logically rule components out without replacing them.

From my little knowledge, it is likely the battery, ignition, or wiring (maybe). I can't see how it could be a grounding issue, because a bad ground would not let this system engage at all, right? So how to check the battery or ignition to rule out...

+1 on the ignition switch theory. My one skill here is electrical. A solenoid is just a set of heavy contacts that close to increase the amps to the starter motor. To operate at all, the solenoid needs the 12V from the ignition switch. If that switch is open, the solenoid has no voltage.

If your ignition switch stayed closed (despite the key position), you would continue to get the cranking.

I don't have real insights on the original "hot starting" behavior, but I would rule out spark by squirting a little starting fluid down your carb the next time you get into a "hot start" situation and before cranking it. If you've got good spark, it should try to fire up immediately. In that case, I'd start suspecting fuel issues. If it just cranks on the starting fluid, I'd go down the ignition/spark track.

Best of luck.
Tom

No, not likely a grounding issue if it starts fine when cold. If the battery is older or in question, replace it (at least 750 cca, 900 is preferred) Use 1 gauge wires, both pos and neg. Use some type of heat shielding between the exhaust and the starter. After that, if you've eliminated the hot start problem see what happens with the cranking issue. It may just go away, probably not though. These old switches have a tendancy to get stuck in the run (car won't shut off) or the crank (car keeps cranking after release). They are cheap enough and easy enough to change.

Any parts store will check your battery for ya.

Ok, let's work this theory. The solenoid does not seem to be sticking based on me pulling it apart and examining, so let's take the starter/solenoid out of the equation for now. The ignition, like you said, provides that 12V to the solenoid. So if I was cranking it over for a while (because it wouldn't start up right away), would that cause some part in the ignition to bind up/get stuck in the 'start' position, thereby resulting in the continual cranking?

I read about somebody fixing the hot start problem buy installing a high torque starter. Thoughts? I thought maybe no since it starts ok normally.

That's a great start Dr. D, thanks!

We'll see how I do when I get home and test the battery.

Not necessarily Tom. You can have all the "good" spark in the world, but if you don't have cranking RPM, then the motor probably won't fire...There's alot of rotating mass in that crankcase and you need that cranking inertia to overcome it. Anotherwords, unlikely a fuel/spark problem.

You can, but with the above solutions, I've been using a stock starter with no hot start issues (used to have them bad) for 15 plus years. If you want to drop the coin on a mini starter, I have no objections

Semi Hi-jack alert::

My '68's hot start issue is a little different. My starter always cranks strong and starts the engine well when cold. But when hot, I get kind of a half try, one-spin "umpf" from the starter. But 99.99% of the time my car starts right up with that. (all stock, everything)

I can tell that if the engine did not fire from this single, one-spin try, I'd be SOL. Whenever the car is allowed to cool down, the starter always spins like it would start a 747.

I wouldn't think this is a battery issue because it always seems to have tons of cca even after sitting for weeks at a time.

As an aside, I NEVER had this issue prior to pulling the engine for a rebuild two years ago. It was an issue immediately after the rebuild. I did not rebuild the starter at that time.
Ideas?

Hi-jack over:

How many miles on the rebuild? Motor could still be a bit tight?

My 2 cents...

Never use starter fluid (ether) on a gasoline engine. It was designed for diesel engines. Just pour a little gas in the carb.

1. Make sure you have a strong battery 900+ cranking amps. Take your battery in to get it checked out at battery supplier.

2. Make sure your posts are clean and wires & connectors are making good contact.

3. Do you have headers? Make sure they do not touch the starter. You will heat up the starter 100x faster if it's touching the header. Does the starter labor more when engine is hot?

4. Follow your fuel line to the carb. Make sure it does not make contact on anything hot. Your fuel could be getting too hot. If you have a clear inline fuel filter you can see it bubbling.

5. What temp is the engine at when it is turned off?

6. Do you have a flex, clutch or fixed fan? Do you have a fan shroud?

7. Do you have A/C filler panels and bottom baffle under the front?

I have always used a stock starter on my cars. I agree that the new ones would work much better though.

If your engine is running too hot you need to solve that first.

Mine was always very tight after the rebuild. Need lots of cranking amps.

sounds like the typical hot start issue...carry a bafg of ice with you next time...if it wont start cool down the solenoid area...see if the helps...you could get a heat shield...$10 from Ames...most likely I`m guessing you got headers?

Talking 'bout your car right???

So for my knowledge, are you saying that when the car is warm, and it cranks over for a while before starting (let's leave the ignition sticking out for the moment), that it could be a battery issue? How is that?

I was thinking it may be a fuel or air issue...maybe the carb is leaking fuel from the bowl, into the intake and flooding it. Then maybe when i go to start the car, it adds more fuel and is too much to start....

bottom line is one problem is affecting the other it seems. Since I have to crank it over for a while when warm, it is plugging up the ignition, casuing it to stay engaged. How do I fix problem 1? Or is the battery/cable fix to help both and I shouldn't be separating it into 2 problems?

And no headers on mine. Fuel squirting into the carb just fine. In liquid form. Car runs at around 190F. Seems pretty normal to me.

600 or so.

Point taken. I was imprecise with my "spark/ignition" phrasing. My point was to separate a fuel vs. electrical issue by trying the start fluid trick.

But I stand behind the starter switch theory. It's must a mechanical switch and it could remain "closed" which could lead to the unwanted cranking.

What else can you rebuild that's tight? lol

The first thing I would do is check the air in the tires.

The second thing I would do is make sure that there were no dead gnats stuck in the radiator.

The third thing I would do is make sure that there wasn't any dust in the tunk.

If all this checks out, I would bump (advance) the timing up a couple of degrees. If I could listen to it crank, I would know for sure, but the only thing I can do is listen to all the hobby guy cars yingyingyingying because of late static timing.


By the way, the reason is keeps cranking after letting off the key is because the contats in the solenoid lighty fuse together.

Do's it crank normal or slower on hot starts?
If slower, try less timing.
If same check carb float level and throttle plate/idle needle screw settings.
Try one thing at a time. If no change, reset that componate and try next one.
Could be 1, 2, or 3 things.

FWIW, i use a 550 cca battery mounted in trunk.
High torque mini starter.
Cranks 24-7 no prob. Sometimes alot with the dam female holley carb w/o choke...

It cranks normal every time. I lowered my float level on my carb this weekend and now it seems to have no problems on hot start. I need to run it a few more times to confirm, but that seemed to do it. Woop Woop!

Ah, glad you got it sorted out...hopefully

The one critical thing we should have asked earlier was the cranking speed...changes the whole approach to diagnosis...our bad.