hard start after running

flatmotor40

flatmotor40

Well-known member
Lately been having to grind starter after running car a while and let it sit fro 5 minutes or so and will grind starter and have to pump pedal to get going.Then it seems to be a little loaded up.2 97's on it.But get right back in and just touch starter button and it fires up.This started about 2 weeks ago.Have 1" spacers under carbs to keep heat off.I used fuel additive to help corn gas but maybe need to add more.Going to try the non corn crap next time.Boy they know how to fix the price on that stuff.Hits first time after I first crank it when I get it out of garage.What else can it be Thanks
 
The fuel pump is actually more vulnerable to heat soak than the carburetor. If you have a backup electric fuel pump, use it to prime the mechanical pump.

The other cause for your hard start would be the coil. Heat soak shorts out the coil, which returns to normal as it cools down. Test the quality of the spark the next time the hard start occurs. The spark should snap a bright blue, not a wimpy orange. Skip Haney in Florida rebuilds coils better than new.
 
It could be your coil going bad on ya. I had the same problem. I went through everything and nothing helped the last thing I did was replace the old coil with a fresh rebuilt coil and bingo problem gone. It worked for me.
Good luck.
 
I have the electronic dist and Mallory coil but it could still start going bad.Just thought it might be the corn gas as some other people have had the same problem.Engine temp stays around 170 on my Moon had guages that are screwed in head.
 
I had a problem like this a few years ago with my '51. When I got my car out in the spring, the battery was dead, so I went to town to get another. All they had was a Group 1 tractor battery, so I bought it and installed it. Everything was fine until the weather warmed up. I got in the habit of leaving the hood open when I parked it on hot days. I finally replaced the Group 1 with an Optima and the problem went away. The Group 1 was 525 CCA, while the Optima is 800, and the Group 2 from Fleet Farm is 725. It seems that a weak or incorrect battery doesn't have the "oomph" to start the slightly larger Ford engine with more cylinders.
 
All bets are off with electronic ignitions on a flathead. They don't do well with excess heat as found under the hood of a flaathead, and they don't do well without computer control. Compromise with a temp controlled electric fan that runs on after shut down. Or, if you really love your electronic ignition, jack it up and roll a new car under it.
 
Always put Optima batteries in all my cars can't stand acid leaks.I'll tighten the intake bolts but this has just started in teh 4-5 yrs I've been driving this is the 1st time I've had this problem with starting after running for say 6-8 miles.I've read before on this site about corn gas giving problems but will try anything.Next is to go the EFI route.All my other cars I've put EFI on and have no trouble.Thanks
 
Since your car has been working well for years, something has recently gone wrong. I'll second the vote to check your coil. A new coil fixed my problem with not starting when hot.

Tom
 
tubman said:
I had a problem like this a few years ago with my '51. When I got my car out in the spring, the battery was dead, so I went to town to get another. All they had was a Group 1 tractor battery, so I bought it and installed it. Everything was fine until the weather warmed up. I got in the habit of leaving the hood open when I parked it on hot days. I finally replaced the Group 1 with an Optima and the problem went away. The Group 1 was 525 CCA, while the Optima is 800, and the Group 2 from Fleet Farm is 725. It seems that a weak or incorrect battery doesn't have the "oomph" to start the slightly larger Ford engine with more cylinders.
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The problem with a weak or low battery is a weak spark. It takes OVER 3 volts to the coil to make a USABLE spark. About 4 volts is supplied to the coil with a fully charged battery which will be in the 6.3 to 6.5 range which is the reading 3 or 4 hours or overnight after a charge. Small cables or bad connections will also cause a voltage drop to the coil. Even with a fully charged battery when the starter is engaged the amp draw of the starter pulls the battery voltage down and when it is down to where it delivers less than 3 volts to the coil the engine won't start. Sometimes under this condition the engine will start just as you leave off the starter button. The engine is still spinning and the voltage raises enough to where the coil receives over 3 volts and it fires. Check the spark from a spark plug wire to a head nut, not to the plug terminal. You should get a crisp blue spark at least 3/8" long. If you get a fuzzy short yellow spark it be luck if it starts. This is why you can push the car or drift it a few feet and it will start as the coil voltage is not pulled down by the starter. Also a weak spark is blown out like a candle from the compression across the plug gap. Any stock Ford coil old or NOS fails when it gets hot. This was what lead people to think the fuel pump was bad from when these cars were almost new. It takes 20 minutes to a half hour to change a fuel pump, the hood is open and after the pump was installed the coil cooled and the engine started. There is internal voltage leakage through the insulation on the coil windings and the treated paper, this is increased with heat. Over the years thicker, higher temperature materials replaced the old varnish. With the new materials which Skip uses in his coil rebuilds these coils should last as long as you own your old Ford. In 20 years and thousands of rebuilds I very rarely ever hear of a failure. Plus he has never charged anyone to repair one other than the few that left the ignition switch on. Even with the switch on you have a 50/50 chance of not harming the coil. If the points happen to be open there is NO voltage to the coil because the points complete the circuit to the coil through ground. If the points are closed the completed circuit causes the coil to be a resistor similar to the ignition resistor. Depending on how strong or charged the battery is determines the extent of damage to the coil. A weak low battery will completely go dead in a short time and the weaker it gets the less heat is generated in the coil with a good chance of no coil damage. A strong fully charged battery will get the coil so hot it melts the bobbin the coil is wound on, chars the insulation on the wire and even expands cracking the outer case. The worst condition would be with a strong battery charger on the battery, switch on and points closed. This could result in a fire. This is why ALL old cars should have a battery disconnect switch. G.M.
 
I"ll check coil but I've never had a coil go bad in all my years of messing with cars.It is a Mallory 12 volt coil.Am going to put non corn gas in and try that.Have a electric pump only on this setup.Thanks
 
I have had a Mallory 12 v coil go bad. Does your starter solenoid have 2 small terminals on it? If so, one of the terminals is connected to the starter switch and the other to the I plus side of the coil, bypassing the ballast resistor. Heat will kill a coil. Try changing the coil.
 
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