Re: hard starting when hot

Posted by Paul Koncak on July 12, 1997 at 12:04:45

In Reply to: hard starting when hot
posted by Wayne Parker on July 11, 1997 at 14:32:22

: My Model A starts perfectly when the engine is cold or has sat for maybe an hour.If the motor is hot and you shut it off to fill with gas and start it up within 2 or 3 minutes, it will start instantly.However, when the motor is hot and you shut it off, and try to restart it, maybe 15 or20 minutes later, it is very hard starting.The only way it will start is with full throttle as though it were flooded.You can't smell any gas like you would if it were really flooded.The hotter the outside temperature is, the more difficult the starting becomes.The engine was rebuilt 5,000 miles ago and does not over heat.Ignition points and plugs are new and the car runs great.It gets +20 mpg.Any thoughts on this?I retard the spark and do not use the choke when the engine is hot.Could it be the kind of gas we use or my starting technique?Could it be carburetor dirt?When I say hot, I mean the car has been driven for at least 20 or 25 miles.
:Again, thanks for the help.
Wyane,
I have had a very simular problem.After replacing "everthing", the problem was found to be the ignition coil.The engine would run fine until it was turned off.Then it would not start until allowed to cool.The reason this occurs is a partially shorted primary coil will place additional load on the battery.At starting time, the load of the starter coupled with the partially shorted coil would reduce the coil output to the point where little or no spark would occur.Thus hard or failure to start.The cooling time was not for the engine, it was for the coil.When it cooled, the resistance changed allowing it to put out the proper spark.
If you are still having the problem, swap the coil with a known good one or check the coil for proper output while the engine and coil is hot.Remove the coil wire from the center of distributor cap and place it about 1/4 to 3/8 inch from the head.While spinning the starter a blue spark should be seen from the coil wire to the head.If it is red or obviously weak, replace the coil.
Have fun!
Paul

E-Mail Comment to Webmaster