Q-jet starting issue

Ben Kallies · 07-30-2007, 05:25 PM

I have a Q-jet on my '71 Corvette Stocker (454/365). Whenever it sits for an extended period of time, the carb will not squirt any fuel. It doesn't matter wether or not the fuel pump is running. So I remove and disassemble the carb, find nothing, reassemble and reinstall the carb and it works fine. This has happened the last 3 times I've let it sit for an extended period. Any ideas? Remedies? Common problem?
Ben Kallies C/S 3869

Mike Hedger · 07-30-2007, 08:34 PM

More times than not when you have this problem on a Q Jet the "main well plugs" in the bottom of the carb are leaking letting all of the fuel seap out of the carb and into the intake where it evaorates. To solve this pull the carb flip it over and take the baseplate off (dont forget to pull the back top long screws out first as they hold the rear of the baseplate) where you will find the plugs,(5 total but the 2 rear/bigger ones leak the most) clean them good with carb cleaner and a tooth brush. Take some JB weld or JB quick and seal them back up. I leave them upside down overnight to let it dry before I put fuel back in it. Hope this helps, Mike

Ben Kallies · 07-30-2007, 09:40 PM

Thank you Mike. I'll try that. If this is occuring, does it make sense that it still doesn't squirt once the fuel pump has pumped fuel back into the carb? Is it possible that the needle is sticking in the seat due to being dry? - Ben

Alan Roehrich · 07-30-2007, 10:16 PM

Quote:

Originally Posted by Ben Kallies

Thank you Mike. I'll try that. If this is occuring, does it make sense that it still doesn't squirt once the fuel pump has pumped fuel back into the carb? Is it possible that the needle is sticking in the seat due to being dry? - Ben

Yes, it is possible that it is sticking. In the other thread, I asked if you had tried pushing the float down. I usually use the plastic straw from a can of carb cleaner, and push on the float through the bowl vent tube. Push down lightly, and release, the float SHOULD push the straw back up. If it does not, turn on the fuel pump, push down again, count to 3 fairly quick, and release. See if it pushes the straw back up.

When dealing with the well plugs, I take a small hammer and tap the plugs to fold the lead edges over. I use JB Weld, it's an old habit from when I used to work at a carb shop, I do all of my Q-Jets that way.

Are you using a nitrophyl float? If not, get one, and set it at 5/16".

Mike Hedger · 07-31-2007, 12:59 AM

One last thought, I wonder if the accl. pump check ball is sticking after the car sits? This could happen if the float bowl is dry from the main well plugs leaking also.
Give it a look the next time you have the top off. Hope this gets you going, Mike

Ben Kallies · 07-31-2007, 11:54 AM

Thank you both Mike and Alan. I appreciate you taking the time to respond. That gives me a few areas to work with. If I find something, I'll let you know. - Ben

07-30-2007, 05:25 PM	#1
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Q-jet starting issue I have a Q-jet on my '71 Corvette Stocker (454/365). Whenever it sits for an extended period of time, the carb will not squirt any fuel. It doesn't matter wether or not the fuel pump is running. So I remove and disassemble the carb, find nothing, reassemble and reinstall the carb and it works fine. This has happened the last 3 times I've let it sit for an extended period. Any ideas? Remedies? Common problem? Ben Kallies C/S 3869

07-30-2007, 08:34 PM	#2
Mike Hedger Junior Member Join Date: Jul 2007 Location: Kemah TX Posts: 93 Likes: 0 Liked 1 Time in 1 Post	Re: Q-jet starting issue More times than not when you have this problem on a Q Jet the "main well plugs" in the bottom of the carb are leaking letting all of the fuel seap out of the carb and into the intake where it evaorates. To solve this pull the carb flip it over and take the baseplate off (dont forget to pull the back top long screws out first as they hold the rear of the baseplate) where you will find the plugs,(5 total but the 2 rear/bigger ones leak the most) clean them good with carb cleaner and a tooth brush. Take some JB weld or JB quick and seal them back up. I leave them upside down overnight to let it dry before I put fuel back in it. Hope this helps, Mike __________________ Mike Hedger S/C 4646 MPH Racing and Fabrication

07-30-2007, 09:40 PM	#3
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Re: Q-jet starting issue Thank you Mike. I'll try that. If this is occuring, does it make sense that it still doesn't squirt once the fuel pump has pumped fuel back into the carb? Is it possible that the needle is sticking in the seat due to being dry? - Ben

07-31-2007, 12:59 AM	#5
Mike Hedger Junior Member Join Date: Jul 2007 Location: Kemah TX Posts: 93 Likes: 0 Liked 1 Time in 1 Post	Re: Q-jet starting issue One last thought, I wonder if the accl. pump check ball is sticking after the car sits? This could happen if the float bowl is dry from the main well plugs leaking also. Give it a look the next time you have the top off. Hope this gets you going, Mike __________________ Mike Hedger S/C 4646 MPH Racing and Fabrication

07-31-2007, 11:54 AM	#6
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Re: Q-jet starting issue Thank you both Mike and Alan. I appreciate you taking the time to respond. That gives me a few areas to work with. If I find something, I'll let you know. - Ben