Long crank times after lengthy shutdown

[Bob Petrasek]

After any engine shutdown of over 6 hours long engine crank times are require to start engine. Less time engine starts immediately. The choke is working correctly. After engine starts it works it runs smoothly. Fuel pump pressure checks out okay. It acts like the fuel line is emptying back into the tank after an extended period. Any like experiences or ideas?

[BIGYELLOW78J10]

What is your starting procedure? For my truck, if I haven't driven it in a week, I put the pedal to the floor once and hold the pedal in as I crank. Sometimes It takes three tries. Always starts. But you should be applying some pedal pressure to start, varying with the amount of time it has been since last driven.
How long is a long time? Long enough to damage the starter? Good Luck,

Daniel

[Dive 30]

what type of temperatures are you experiencing? Your carburator bowl should store enough fuel for start up and run until your fuel pump catches up. Over time (as in a couple of days) the fuel in the bowl will evaporate and it will take some time for the fuel pump to refill the bowl. Have you re-built the carb lately? Needle/seat,float, and valve adjustments are critical for proper start and run. I would start by looking for fuel leaks around the carburator (bad mojo, cause fire). Be sure to look at all of the seals, especially around the diaphragms. Especially look at this if the vehicle runs fine once it is started. A clogged fuel filter can cause inadequate fuel supply, but it sounds like you've inspected that. Guys . . . have you ever seen an electrical problem that would cause this? I've never had a coil/ignition problem that didn't just die. I've seen some postings on bad coils that caused gremlins, also bad ignition modules, but I'm not experienced with them (knock on wood). Hope that helps.

[Bob Petrasek]

I am fairly certain that it is a fuel problem. The a new remanufactured carb was put on about 18 months ago. The problem has always existed when the engine sat without running for more then a week. Now it is down to about the six hours. When the engine is cold I close the choke with the accelerator then crank the engine. It will crank for tewnty five to thirty seconds before it starts. If I pump the accelerator it will start in twenty to twenty five seconds. Once it starts it runs normal. The fuel pump is about two years old. I have not yet gone through the low pressure supply line to the fuel pump. I did read a previous message where someone capped the fuel return line and stopped a somewhat similar problem. I will try to vacuum test the supply line between the fuel pump and the tank to rule out cracks or pin holes.

[DerJeep]

Before starting next time, check the fuel level in the bowl. If low or empty, you could have a bad power valve/gasket or the fuel pump may be allowing fuel to backflow (Veepster mentioned something about this about a week ago), essentially sucking fuel out of the blowl back to the tank.

[mechanic58]

I have an 89' GW and I too have had the same problem. I got the truck with a blown engine in it and I just put a brand new 360 back in it. It's all stock except for the removal of ALL of the emmissions control equipment. (PAVE THE EARTH) As soon as I began running the engine and for the few days that followed, it took several attempts to start it after it had been shutdown. Turns out the the power valve in the carburator was leaking and all the fuel in the bowl was leaking into the intake. If I tried to start it about 15 mins after shutdown, it acted like it was flooded (obviously) and if was several hours or more, it acted like it was out of gas. If you have a motorcraft 2 barrel on your engine, then this is the most likely cause of your problem. The way my carb is set up, if the power valve is leaking, the gas the leaks past it goes right into the throttle body via a vacuum passage. Takes almost no time for the bowl to empty when the engine isn't running.

[JeepFreak]

I have the same exact problem with mine. I know mine is the fuel pump because if I pull the fuel line off after she has sit for say 10 to 20 minutes I can hear the suction from the line when I remove it from the carb. Manual pumps can get pin holes in them and create a vacuum on the line making it hard to start.

[Bob Petrasek]

Thanks for the tips and experiences. I will give the fuel pump and power valve a through exam this weekend.