I have a 69 skylark with a 71-350-4 motor. I had the original carb rebuilt (Q-jet) about 2 months ago and it runs great. If the car has been sitting for about a week or longer it takes 5-10 seconds of cranking the motor and pumping the gas to get it started. After that it starts up almost everytime. I have replaced fuel pump, ignition wires, spark plugs, high torq starter and updated to an HEI system. All hoses are new. Is this normal. I hope not. Please give me some ideas of how to diagnose and fix. Thanks
The float bowl has "plugs" in the bottom. 9 times out of 10 these plugs develope leaks. When sitting, the gas drips out of these plugged and leaking holes. Then when you go to crank up the next time the fuel pump has to re-fill the float bowl.....resulting in the long crank-time. When I rebuilt my Q-Jet, I used epoxy to encase the plugs in the casting to stop this very issue. Worked like a champ.
A related problem: If the float bowls drain a bit, the float drops, and opens the needle valve. If the check valves in the fuel pump aren't perfect, the fuel line from pump to carb siphons to the level of fuel in the tank. Not only are you pumping the carb bowl, but also the volume of the fuel line, too. Note that you may still get acceptable pressure and volume from the pump-if the leak is small enough. But even a very small leak will drain the fuel tubing overnight. A band-aid fix for this is to install a replacement in-the-carb fuel filter with a "safety" check valve. They cost almost nothing. If the problem disappears, replace the fuel pump. Should be a warranty deal for you, since it's fairly new.
I'm not sure if I have a Q-Jet, but my car seems to experience the same problem of slow starts. Also, for about the next 12 hours after I've had it running, it reeks terribly of gasoline. Could I be having a leak in the carb, that has created/contributed to both problems? ~Mike 66 Skylark 340-4
Something to remember here is simple. Gasoline is not the same as it was thirty years ago. It vaporizes very quickly, since it is now formulated for the constant pressure of fuel injection. It is verey likely that the fuel, while sitting in a very hot carb float bowl, will evaporate quickly, causing its share of problems in its wake. The fuel will likely leave a brown or red deposit similar to varnish (it is exactly that). Cheaper, no name fuels exacerbate the problem. Though the plugs at the bottom of the float bowls are known for leaking, this problem leads to flooding, after short time of sitting. After a couple hours of sitting, it will require holding the throttle on the floor, and a cloud of black smoke when it starts. After sitting for a few days, the evaporated fuel will require refilling of the float bowl, the pump, and the lines. In some cases, the deposits will prevent the float from dropping, requiring a spray of carb cleaner, or even carb disassembly to fix. I am not saying that you should ignore the fuel smell. Anytime raw fuel is noted, the source must be located in order to prevent a fire, but bear in mind all of the possibilities, including fuel quality. The vapor cannister, purge valves and the filler cap all can have an effect on fuel control, leading to a myriad of problems. Ray
Ray is right on here. After two or three days of sitting mine won't start because the bowl is empty. The plugs were "sealed" about 10 years ago but even then it still had the same problem. I refuse to crank and crank. Wanna waste your engine? I give the engine a quick shot of starting fluid if it's been sitting more than two days.
My engine does this too, and I have a John Osborne Q-jet. The fuel bowl on a Q-jet is very small, the gas just evaporates I think. I just crank it for 5 seconds or so, then pump it 2 or 3 times, and it fires right up. If you want to go through the trouble you can fill the fuel bowl through the vent with a small funnel.
excessive cranking these guys are right. if you want to fix the problem or help it alot is to install an electric fuel pump. just a thought. jerry :Smarty:
Choke? Also check your choke and fast idle , if there is no choke on cold start the engine will require an excess of fuel, I thought I was getting drain back until I set the choke.
long cranking time on startup I use an electric fuel pump in tank with a switch. Whenever I startup after setting I turn the electric fuel pump on for a minute she starts right up. Also whenever I change the carb or work on it I can fill the bowl and don't have to crank the engine. Bernie Steffen.
