I've got maybe 1100 miles on this crate 385. It runs great when warm, and starts easily if recently run. However, parking it for a few days or longer makes cold starting a real chore. The longer it sits, the longer it takes to start.

I have a Quick Fuel 780VS and a Holley manual pump 12-327-11 both of which came with this engine. The old 350 using an Edelbrock carb and pump wasn't nearly this hard to fire up.

Float levels are perfect when driven. But after a long duration, I assume the empty float windows are indicating fuel evaporation, and the length of cranking time it takes to get a fuel pressure reading indicate some backflow into the tank possibly?

I'd like to hear from others using similar equipment, are you using a check valve in the fuel line? Anyone solved this by replacing the manual pump with electric?

 

Once the gas gets past the needle and seat it cannot flow backward thru the fuel lines. Are you saying the fuel level in the float bowls is dropping between engine starts? If so the bowl gasket is leaking. The mechanical fuel pumps should not leak backwards IF the check valves are sealing and I had a Pierce mechanical pump do just that from the moment I installed it.

 

No drop between starts. This is just a recent discovery, but it must be taking days or weeks for the float levels to fall off like that. Its garaged for the winter so I'll have to check it every weekend to verify the rate it is dissipating.

 

If your gas tank isn't full and you do have a fuel pump that is leaking back I could see it taking a bit longer to start if the gas in the carburetor is evaporating.

 

Although I have never installed check valve to correct his issue...I am not 'saying' that it could not help. I just do not know.

What I do know is that YOU will need to do some diagnostics...if you have not already.

IF you know the car will crank and run rather easily the NEXT day after it has been driven....then I would begin to check it every few days and see what you find out.

In situations like this....I will come in the next few days and manually throttle the carb and watch and see IF the fuel immediately begins to squirt....and how many squirts it takes to go dry and no more fuel coming out. NOW I do place some sections of paper towels down in the carb to catch as much fuel as I can...and pull them out when the carb has been run dry. Then crank and run the engine and let that fuel clear out if any dripped past the paper towels....drive it and bring it back and when it has cooled a little bit...DO this same test again and see what the carb shows for the amount of fuel that is now know to be CORRECT.

Then...when the time has been established where the problem begins. I then would CAREFULLY disconnect the fuel supply going to the carb and route it into an approved container for fuel and disconnect the power to the distributor...and spin the engine over and see how long it takes for fuel to pump correctly. I count the number of engine revs.

You can do this test after three days or ten days and see if this variable changes. SO...if you install a check valve...you have a KNOWN and will be able to see if the check valve aids this issue. This 'check valve' may do the trick because the reservoirs in a factory style pump are much larger to hold more fuel and have it ready to get to the carb when the engine is spun over.

Having your fuel tank full means nothing. And with the fuel pump being lower than the fuel tank.... how can the fuel can get lower at the fuel pump when the end of the pick up in the tank is higher than it.....and the FUEL is not under pressure flowing backwards from the carb....and EVEN if the fuel tank was under pressure due to not being correctly vented....if anything...the fuel would possibly get past the needle and seat and drip into the engine. The only possible scenario that I can see is that your fuel cap is NOT working as designed and for some strange anomaly...the fuel system has a vacuum on it when the engine is turned off and it is sucking the fuel back into the tank...that is the only way I can see that happening.

DUB

 

Thanks Dub, We're at day four monitoring the fuel level in the float windows which is still correct. There have been no fumes so I don't think gas is leaking into the intake. After we're done with Christmas I'll probably try pumping fuel into a can after various lengths of time. That might tell me if the check valve would help. I only have 1/4 tank now. I may have to test this again with a full tank and see if it changes anything.

 

I suggest you check your choke to make sure it is actually working as it should. If it is not the motor will fire and die and you may actually flood the motor in your attempts to start it. If it is working as it should then move on to a fuel delivery issue which should not stop you from starting completely, it should behave as a cranking start and a stall from loss of fuel. Because even with a drain back your accel pumps offer enough gas to fire the motor briefly.

ALSO CHECK OiL for a strong gas smell.. The pump may be bad ..

But if you are draining back I would check to be sure the tank's vent is working.

 

EXCELLENT SUGGESTIONS/ADVICE!!!

If you can see that your fuel level in the blows are fine even after a week or two. The I also would be wondering if the choke is set correctly.

When the engine is cranked when COLD...to should go to the fast idle. So..pumping twice(or how ever many pumps of the gas pedal you choose)....should set the choke....turn the ignition key and when the engine is cranked and running it should be on a fast idle. And if the fuel pump can catch up fast enough to keep the bowls full of fuel...the engine should not die.

DUB

 

Just an observation but I used an anti-drain back Napa inlet filter with the check valve as recommended by Lars and found that under acceleration, the carb ran out of fuel. It would die under heavy pedal and the inlet on the filter was the problem as it wasn't opening properly.

 

I am assuming that this filter went into the fitting of your Quarda-Jet.

It is possible that the carb that the OP is using has the capability for a fuel filter to be installed in the fitting that goes in the bowl.

Good to knwo that you had a problem and found out what caused it...so far...I have not ever had one of these filters with the check valve cause for fuel starvation when under acceleration.

But being a HOLLEY design type carb that the OP has...the fuel fitting is up high on the bowl and the bowl should not drain back due to the fitting is higher than the accelerator pump.

DUB