Discussion Forum - Northstar Chevelle Club

jim larson · 2K+ Club

Any way to avoid hard start problem after Chevelle has been siting for a week or two?

dashboard · 2K+ Club

Jim I know some guys that have installed electric fuel pumps to function as a momentary boost pump during start. They mount the pumps back near the tank, it is only used for starting. I have the same issue with both the Elky and GS. I think it's a combination of fuel boiling off after shutdown and fuel running back to the tank.
I had two pumps waiting on the shelf for me to install, just haven't had time, I sold one to a buddy that had the same issue with a 65 GS 401 two four setup. Fixed his problem; today's fuels just are not formulated for these cars.

Now, having said all that, and living with the issue for years, I know guys with big blocks that don't have the problem.

jim larson · 2K+ Club

Well here is a strange update regarding the issue. A guy suggested manually operating the accelerator rod, if the accelerator pump goes dry after 6-8 pumps,the fuel bowl has lost fuel; 10 pump and fuel still going into the carb bowls, it is good to go.

So after 2 weeks, I operated the rod 20 times and fuel was still squirting into the carb bowls. This was after putting a pipe cleaner in the site plug, which indicated there was fuel. Well after the 20 pumps, I turned the key and it started right up after what seemed to be one engine revolution? Well maybe it wasn't getting enough gas??

I will have to try that procedure again after the car sits for a week. Hoping the car starts right up tomorrow.

Chris S · Active Member

Keep us posted on this Jim. I have the same issue with my car and I agree with your lack of fuel theory. I have been pumping the throttle a little more each time I start it and I am yet to reach the point of too much fuel.

Bobs_Place · Vice President

Jim

I have had the same problem, didn`t think to much about it.
But now that you bring it up, I have been making alot of changes on my carb.

I always remove the carb from the engine to make the changes.
I then drain the fuel from the bowls before I remove them.
One time after the car sat for 2-3 days I found the primary fuel bowl was almost empty but the secondary was full.
Sometimes when I pull the bowl and metering block I find the gasket and gasket surfaces are wet with fuel.
I would think that by draining the fuel before removing the bowl and metering block that the gasket would not be
wet with fuel unless the gasket is leaking.

It is my thought that the fuel is leaking internally. The fuel would travel through the main jet across the metering block
gasket to the idle feed than into the manifold, or into the vacuum port for the power valve than into the intake.

Just a theory, hope this helps.
I`ll pay closer attention in the future when I make change to the carb.

Let me know if you find any thing.
Good Luck

OscarZ · Treasurer

I had a similar issue long ago but for me the problem was the rubber lines off the gas tank that connected to the hard lines were old and cracked where they bent. They never leaked to the point of being noticeable but were cracked enough to dry out and take awhile for gas to get flowing normally. Once started and I went for a drive it would restart just fine. Only after sitting awhile did the gas drip or evaporate enough to be a problem. Spent lots of time messing with the carb and lots of money on a fuel pump, pressure regulator and gauge only to learn it was a couple dollar and ten minute fix.

Lost in the 60s · President

GM has had this issue for 40 years, gas draining back out of the carb. Their "fix" then was a check valve in the paper fuel filter at the carb. It worked, but they only fit Rochester carbs, so it's basically a moot point. ALL my cars do the same thing after sitting. If it has only been a few days/week, I can pump the pedal 6-8 times before I turn the key and they usually start right up. Longer than a week or 2 and I have to crank until the pump fills the carb again.

I've been looking for an in-line check valve to install right before the fuel pump but haven't been successful at that.

jim larson · 2K+ Club

Hey Mitch, my brother who is an airplane mechanic in AK also suggested the check valve in the rubber hose just before the fuel pump.

How about something like this ?

Enganeer · Mega Poster

Concept is good but not for single line fuel systems...see last line for product

WARNING: Do not use on returnless fuel systems

jim larson · 2K+ Club

On the 66 they had a single line, 3/8 for the 396 or 327, no return line. Not sure when that started, maybe 1968?

Pumped the gas five times today, started right up in less than one revolution, I think, so maybe all is good, just need to pump the gas a little or use an old oil can to put gas directly down the carb when sitting a long time. Will have to check again when car sits for a week or two.

Bobs_Place · Vice President

I have a 3 line pump, they are used with A/C cars.
I find the fuel line at the carb always empty, the return line will drain the fuel back to the tank.

Don`t bother with check valves as they will cause restriction, and, a fuel pump has check valves to prevent any
back flow when it pumps.' If it is a 3 line the fuel will only bleed back through the return.

Once the fuel flows into the fuel bowls it can`t flow back into the fuel line as it would have to flow up through the needle and seat.

Pull your sight plugs to check the level before start up. Might be interesting to see what the levels are.

19 CHEVELLE 66 · Newbie

No one is concerned about the gasoline washing down the cylinder bores?
I would think that pumping the carb. 10-20 times would cause this. I have
thought that one or two pumps is all that is needed, if the fuel pump and carb
are in good order.

Jon H · 1K+ Club

I guess I am the exception. A day or two and one pump to set the choke. One to two weeks and two pumps. The only time I need more than that is spring start up.

Grajmahal · Active Member

I did the "Mr. Gasket" fuel pump trick back by the gas tank, but it's noisy as hell. It is unplugged at the moment, and because I drive the car as often as possible, I don't really need it. My plan has been to put a hidden switch somewhere under the dash for when it's been a couple of weeks since she's run, or I am experiencing vapor lock.

John