[Bruce Meyer]

I normally run Holleys on my cars but since this particular car is a matching #,s 4 speed 69 GTO Im running a Q-jet on it to keep it original. The problem Im having is if the car sits for more than 2 days the fuel bowl is empty and I have to prime the carb or wear out my starter cranking it to fill it back up. I had sent this carb to Cliff to put in the screw in plugs in the wells so hopefully its not draining out when shut off. My Holley equipped cars can go over a week and still have fuel in them to start.
Is this normal for Q-jets?

[tom s]

I have found the same thing with QJs and to a lesser degree with my AFBs.Tom

[Kenth]

10 seconds on starter may seem like an eternity before start compared to a modern fuel injected car with a closed to atmosphere fuel system and a start button.

Not uncommon with todays fuel evoparates out of fuel bowl in a couple of days.
Should not take more than 10 seconds on starter for fuel pump to fill the bowl.
I would say normal for a carb with center located small fuel bowl.
IIRC this is mentioned in the owners manual.

BTW, 1969 and later Q-jets seldom if ever leaks thru the bottom plugs like the 1968 and earlier unit were plagued with.

FWIW

[burd]

My car sits for months and starts rite up. Something is wrong.

[Gary H]

Yes, today's gas will evaporate out of the bowl in a few days. It also has a low temperature boiling point which causes issues with vapor lock and vaporization after switching the car off and trying to restart it after it sits a few minutes. I deal with it with customers constantly with carbureted cars.

[MNBob]

I was never able to fix that on my 79 and it got really annoying. I had the plugs in both the big and small wells, the float adjusted, and a new one of Cliff's kits. Nothing helped.

Finally, I went to a Sniper QJ which has been great. Still have to wait for a fuel prime though.

[mgarblik]

Yes, the fuel can evaporate over time, but shouldn't take that long to restart. Couple things to check. When you park the car, hot. Take the air cleaner off and look into the carburetor after it sits for 10-15 minutes. If you see fuel dripping out of the center of the venturi, an air bleed is plugged and the bowl is siphoning itself empty. Also look into the manifold below the throttle plates to see if it's wet. Does the car smell like gas when it sits hot?

[Bruce Meyer]

Originally Posted by mgarblik

Yes, the fuel can evaporate over time, but shouldn't take that long to restart. Couple things to check. When you park the car, hot. Take the air cleaner off and look into the carburetor after it sits for 10-15 minutes. If you see fuel dripping out of the center of the venturi, an air bleed is plugged and the bowl is siphoning itself empty. Also look into the manifold below the throttle plates to see if it's wet. Does the car smell like gas when it sits hot?

The car doesn't stink up the garage any more than the Holley equipped cars. Actually it smells less than the Holley cars. We have alcohol mixed in the fuel here in Phoenix. Plus the car has open exhaust crossovers and the Holley ones are blocked.

[prostreet64]

I know you are trying to keep the car original, but that issue with QJs is one of the reasons we went to electric fuel pumps on our cars. Just flip the switch for a few seconds and fill the bowl before cranking.

[GTOLou]

Originally Posted by prostreet64

I know you are trying to keep the car original, but that issue with QJs is one of the reasons we went to electric fuel pumps on our cars. Just flip the switch for a few seconds and fill the bowl before cranking.

This 100% - I think ?? ethanol evaporates faster too? I try my best to not run 10%ethanol gas in any old car or power tools/chainsaw.

[77 TRASHCAN]

100% gas is readily available in Oklahoma, it's all I use, in everything...

My TA sits for long periods between starts/runs. I turn the key for about 5 seconds WITHOUT touching the gas pedal, then pump the pedal twice, spin engine 5 more seconds. It usually starts. Getting gas to the carb is the first priority...

Some folks turn the key and visciously pump the gas pedal, trying to starts. This seems to be a formula for flooding, usually to me...

[Bruce Meyer]

Well after I read mgarblik post I took the car for a long drive, after I primed the carb, and got it nice and warmed up. I let it set for 15 minutes and looked down the carb. No dripping. It looked dry. I already thought about an electric pump but Im going to let the next owner deal with it. But I will inform whoever buys it that's its a typical problem with todays fuel and the thimble sized fuel bowl that Q-jets have. The thing that's a bit of a bummer is that of all the Q-jet Pontiacs I have owned this carb runs the best hands down.
Thanks for the replies everyone.

[Brian Baker]

I have the same issue with my 68K original mile Can Am, but only on a cold start after it has been sitting for weeks, so I attribute it to the fuel evaporating. Hot starts are no issue.

[Cliff R]

Empty fuel bowl(s) after sitting a few days is normal.

LONG periods of cranking to re-fill the bowl or having to prime it is not.

The fuel bowl should re-fill quickly and engine roar to life after 1-2 cycles of cranking for 4-5 seconds. If not there is something else going on keeping the fuel from returning to the fuel bowl.

I see this a lot. Could be as simple as a loose hose clamp on a rubber line, or defective mechanical pump, etc.......

[Greg Reid]

I had the same problem with my '68 ('74 q-jet) for years until I recently rebuilt it...and I mean to the point that I would get a small bottle and pour gas down the vent tube.
It can now sit for months and it takes no more than 8~10 seconds of cranking. This last build was the first time I decided to re-install the choke as well. I attributed at least some of the change to that.

[Cliff R]

I have 2 John Deere 318's and a 212 here. If they sit more than a week the fuel bowls are empty. It takes at least two pretty long cycles of cranking to get the fuel bowls full again. As soon as fuel returns to the carburetors they roar to life instantly. Never had this issue with them the first 20 years I owned them, just since this new fuel came out. Not sure what they are making it with or from, but it does NOT stick around very long in a vented carburetor whether it be on a car, truck, or anything that uses a mechanical fuel pump to keep the carb full. I've taunted the idea of replacing the diaphragm pumps on those tractors with electric as I actually knocked the starter out of one of them last summer (engine removal required to replace it)..........FWIW......

[GoGoat]

Not to hijack this thread. I wonder which is better on my engines after they sit the winter out for 5-6 months. Cranking engine for 20 seconds without pushing gas pedal to prime oil and fill carb- then pump pedal and start car. Or fill carb thru vents and get engine to start quicker? Thanks for great web-site.

[Sirrotica]

FWIW, my last job before retiring was delivering wholesale fuel to retail outlets. If somehow there was a fuel spill during the filling of the tanks in the summer time. If we happened to spill fuel on the asphalt before you could get the absorbent towels out and put them on the fuel the majority of the fuel would evaporate.

I would equate the temperature of the asphalt to the under hood temperatures very closely, 120-140 degrees. and it evaporates very quickly with ethanol added to the fuel. The more additives they use in certain geographic areas in the summer time to try to reduce emissions is also another thing that makes the gas evaporate quicker.

I know that 100% gasoline doesn't evaporate anywhere near as quickly as ethanol/emission additive laced fuel does. if you can get 100% gasoline, it should help the evaporation problem on a Q jet equipped car. Problem is it isn't available everywhere in the country. Many times marinas have the 100% gasoline as ethanol doesn't play well with carbureted engines on the water that are stored and used somewhat the same pattern as hobby cars are.

The Holley float bowls hold much more fuel to start with, so it's going to evaporate over a longer period.

Many years ago when ethanol fuels were first introduced, Nissan/Datsun used a small fan located on the intake manifold to blow air on the carburetor after the engine was shut down to reduce the evaporation and vapor lock problems encountered before fuel injection became standard. It was a stop gap, but as far as I can tell it worked pretty well for cooling the carb down after engine shut down. I had a customer that owned one of these cars with the fan on the intake manifold that never seemed to exhibit problems with vapor lock, etc.

[Schurkey]

Originally Posted by GoGoat

I wonder which is better on my engines after they sit the winter out for 5-6 months. Cranking engine for 20 seconds without pushing gas pedal to prime oil and fill carb- then pump pedal and start car. Or fill carb thru vents and get engine to start quicker?

No question--prime the carb(s) so the engine starts easily/quickly.

1. No excess grinding on the starter/ring gear

2. Faster/more oil pressure, faster oil splash on cam and cylinder walls, faster lube to rocker arms

3. Doesn't drain the battery, doesn't heat the starter motor

[DogMeister]

Originally Posted by burd

My car sits for months and starts rite up. Something is wrong.

With a Quadrajet?