help with hot start

[phanatic32212]

Here's the problem. When I start my truck in the morning, It starts no problem. I need to give the gas a tap or two to get it running good, but after that it runs fine. I can drive for a while with no problems. After I shut it down, if I try to start it within 10 minutes it will start right up. But, if I leave it sit for an hour or two, i will turn over but won't start. There is fuel going to the carb. It will eventually start with a good amount of gas, just not like before. I look in the fuel filter and there is little to no gas in the filter, almost like the gas is running back down to the pump. I don't see any leaks or cracks in the line or fuel pump. Any ideas on what would cause this?

Thanks in advance.

[ChevLoRay]

I have one of the glass filters on my truck. I could smell gas, but didn't think anything about it. On a whim, I replaced my "rubber" fuel lines from the pump to the carb. Smell is gone, and it starts right up. It had fuel in the glass before, but it wasn't full of fuel. I don't think you are getting enough gas after it sets, just like mine did.

[PanelDeland]

I have seen small pin holes or undetectable cracks let fuel drain back.The carb float bowl should still have enough fuel to start the engine though.I would check or just change fuel lines and filter and maybe check the fuel pump.

[68gmsee]

My guess:

The fuel is being drained from the bowl area of the carb into the intake causing a flooded condition. Cranking it for a length of time will usually restart it.

You say that fuel is getting to the carb after it sets and that it cranks right up after sitting overnight. The only thing that comes to mind is a flooded condition preventing it from starting right up.

I would take the carb apart and give it a good cleaning with carb cleaner and maybe replace the needle valve.

[phanatic32212]

The thing is it just started doing this. I haven't changed anything to cause it. I can see through the filter and shortly after I shut it down, I can see bubbles coming up through the line and into the filter.

[wibilly]

smell your oil if it's getting flodded that much that often the oil would become contaminated and lead to an early death. my guess is, it is caused bby one of two things, one is evaperation from a hot intake and improper gasket or heat shield, two is no ckeck valve in the fuel filter which the filters in the fuel inlet in rochester carbs had. you could also have a weak fuel pump compounding the problem

[cdowns]

what do your spark plugs look like

[phanatic32212]

I checked the oil, nothing out of the ordinary. Aside from a little carbon buildup, the spark plugs look alright. The engine has been running rich for a while now, which explains the carbon. With the glass filter that I have, when I shut off the engine, I can see the fuel slowly drain back towards the pump. This has never happened before, it has always held fuel in the filter. Is this my problem and what would cause that? Thanks again for all of the quick responses.

[cdowns]

theres a piece of rubber hose under the cab on passenger side where the fuel line from the pump connects to the line from the tank check that for crackjs

[68gmsee]

Since you don't suspect flooding I'd go with the fuel pump. They're cheap and easy to replace.

If you haven't replaced it in a long time, I would do it anyway because the diaphragm can go bad. It will crack and allow air in causing fuel to drain back down. Also will cause the pump to be weak as wibilly mentioned. I had mine do the same thing on my 69 a few months ago.

The thing that's got me thinking flooding is that you can start it right up except when it's hot. If the spark is there then it usually indicates one of two things. Flooding (fluid dripping into the intake) or no fuel in the carb bowl. Still could be caused by needle valve sticking or dirt/grime in the bowl.