Engine is hard to start when warm

[The_Handier_Man1]

From: Fader  (Original Message)
Sent: 6/26/2002 2:21 PM

My '73 Minnie is suddenly hard starting when warm. Cold, she starts the first time (on two kicks of the gas pedal). She will also restart hot with no trouble (ie. restarting immediately after shutting off). But... a thirty minute cool-down and I'm grinding the starter and pumping the gas! I've heard that fuel grades change from winter to summer, and we're right at that season where the temperature has risen about 10 degrees. The other thing I did was clean the carburetor with Berryman's (linkages, choke, throat, and PCV valve).

Hoping I don't have to take off the dawg house again,

"Fader"



From: Dave1210 

My old 1970 F250 does this.  The cast iron intake radiates heat causing the fuel to get very hot in the carb, putting a spacer in between the intake and carb is supposed to cure this. Can't say for sure whether this will solve your problem though. Good luck



From: Fader 

...so, I remove the dog haus, jiggle all of the vacuum hoses, shake up the butterfly and -- viola! Seems to be back to normal.

"One hit is maintenance, two is abuse"

Time to hit the road instead of the carb



From: Fader 

I will be aware of fuel lines too close to manifolds. But, the dog haus is closed



From: nvdesertrat0775
 
Two things you said make me think of a sticking choke. If it was vapor-lock~ having the fuel line too close to a hot part~ it would be more likely that it would stop running when it became warm, rather than only being hard to start.  The fact that you can "jiggle the butterfly, etc" and get it to start, hints that the problem is there rather than in the fuel line.  I suspect when you cleaned all the parts it somehow caused the choke to start sticking.  A little silicone lubricant sprayed on the moving parts might solve it.
   If it acts up again and you can get to it easily, you might want to ~gently~ test the choke (butterfly) to see if it moves freely.  If the motor is hot, the choke should, naturally, be wide open. I suspect it will be partially closed, making it easier to start cold than hot



From: pugsley 

Check and see if you have a Rochester (thermoquad) carb. Its a poor design,
the plastic cracks allowing fuel to seep into the intake causing hard starts.
It could be something else too.



From: Fader 

I watched the choke. After driving the rig until hot, the choke closes when the engine is shut off. It will open and restart. I've usually had problems after it sits for 15 minutes or so. I've lubricated it and the choke seems to move absolutely freely. I suspect I will need to have the carb rebuilt after the trip (it's a 2 barrel). It also runs rich and puts some black soot on the driveway (anyone know how to get that out?).

At least I now know the emergency start procedure -- pull the dog house and wiggle stuff .



From: nvdesertrat0775
 
Between "jiggling stuff" and duct tape, we can fix dang near anything!!  The next time it won't start, peek at the choke and see if it's open or closed.  In fact, BEFORE you jiggle anything, study the position the various parts are in, and then after jiggling~ when it WILL start~ see if anything has changed position.
  I alway figure trying to guess why a vehicle behaves as it does is a lot like trying to guess why a baby is crying. By the time you figure it out~ if you ever do~ it's already changed.



From: jvf 

My 318 2-bbl acts similar to what you describe.  It starts cold but if it dies before it gets fully warmed up it is almost impossible to restart.  If it is hot no problem.  I found the choke opens all the way up before the engine is fully warmed up and I have had to open the dog house and manually close the choke to get started.  I have been trying to adjust it so it will stay partially closed until the engine is hot.
Perhaps this is what is happening to you.



From: nvdesertrat0775
 
Check your vaccuum lines.  Sounds like you might have a leak that could cause your advance to not function correctly. By not advancing when it needs to, it could cause really hard starting if it dies, but if it runs long enough the advance finally has time to catch up.
  If you have the same 318 2bbl type as I have, with the electrical choke, one of your wires could be loose.
  Or,  it could just be set wrong or ready to be replaced.  If you DO have the same electrical choke that I have on my 318, it's set just a hair past the 4th notch.



From: jvf 

The vacuum advance is working, I just installed an electronic ignition and readjusted the timing.  I checked to make sure the advance was working with the timing light.
The electric choke is working because when the engine is cold it is closed and then opens completely before the engine is very warm.  The engine starts right up if I close the butterfly manually.  I have been playing with the adjustment try to keep it closed longer.  I will compare it to the 4th notch you recommend.  By the way, someone was wondering if a sensor controlled the electric choke.  I don't think so.  I am pretty sure it is just the 12 Volts from the ignition switch, but I could be wrong.  I know if I leave the ignition on for a while the choke opens and that will make it hard to start.



From: Fader 

Emergency Hot Start Procedure:

(Used every time I start the Minnie)

1. Make sure no one is standing on either side of rig
2. Hold gas pedal to the floor
3. Crank

This is what's working for me. It is not subtle, but it is effective