Put on Q-jet, now car won't start

[dan2286]

I decided to try out this Q-jet I had sitting around. Was rebuilt a while ago and used for probably less than an hour. Since putting it on, it took a very long time to start. It eventually did start, but after shutting it off it would not start again. The engine was running for maybe 5 minutes. Waited about half an hour and tried starting it. It eventually started, but still took a long time. I believe I had to have the pedal to the floor to start it. Took it for a drive and it ran really good. Great throttle response and ran very smooth. Seemed to be lacking power, but still will roast the tires. Hoping some adjustments can fix that. When trying to start it, I have been opening and closing the choke, but still doesn't want to start.

Is there any common problems that could cause this? I am sure It is flooded now, but there is still an issue with the carb. Any help would be greatly appreciated!

 

[G-Body_Vet]

I decided to try out this Q-jet I had sitting around. Was rebuilt a while ago and used for probably less than an hour. Since putting it on, it took a very long time to start.

Did you prime it with fuel first or wait until the pump filled the carb bowl?

It eventually did start, but after shutting it off it would not start again. The engine was running for maybe 5 minutes. Waited about half an hour and tried starting it. It eventually started, but still took a long time.

Sounds like it could either be a sticking choke, flooding, or maybe low float level. If you have someone that can crank it for you, see what the choke is doing. DON'T put your face directly over the carb though. A backfire to the face wouldn't be cool.

I believe I had to have the pedal to the floor to start it. Took it for a drive and it ran really good. Great throttle response and ran very smooth. Seemed to be lacking power, but still will roast the tires. Hoping some adjustments can fix that. When trying to start it, I have been opening and closing the choke, but still doesn't want to start.

Is there any common problems that could cause this? I am sure It is flooded now, but there is still an issue with the carb. Any help would be greatly appreciated!

I don't think the accelerator pump would have anything to do with this since the response and idle is there. I'm suspecting too little fuel in the bowl, possible from an improperly set float. I'm no carb expert, but that's what I'm assessing from your description. Out of curiosity, is this a non-CCC carb correct?

 

[dan2286]

Thanks for response. I primed carb with starting fluid through vent, don't know if that was a good idea or not. Choke tubes are not hooked up, so I have been manually moving it open or closed. Everything choke wise seems to be operating as it should. All linkages move free, fast idle kicks down, and secondary lockout disengages. Carb is non ccc.

Car's been sitting for a while so I will see if I can start it.

 

[G-Body_Vet]

What's the history on the car itself? Was it previously running or has it sat for awhile too? Any chance the fuel filter is shot?

 

[dan2286]

What's the history on the car itself? Was it previously running or has it sat for awhile too? Any chance the fuel filter is shot?

Previously running. Was sitting maybe a couple weeks. Need to check fuel filter.

Tried starting after sitting for a couple hours. Was a pain to start again. It did eventually start with choke closed. Was playing with idle mixture screws and must have turned it too far because car died. Car is getting lower vacuum, that's why I was trying to adjust idle screws. Now won't start again The thing that is confusing me is that the car won't even try to start when using starting spray!

I'm thinking this carb will need to be gone through again. I guess I will put the POS Holley on for now 😢

 

[megaladon6]

i thimk the carb is running very rich. that's leading to fouled plugs.
i'd pull the plugs, clean 'em (MAPP gas torches work great) start the car and start tuning via a vacuum gauge. don't forget that you MUST adjust timing at the same time.

 

[dan2286]

i thimk the carb is running very rich. that's leading to fouled plugs.
i'd pull the plugs, clean 'em (MAPP gas torches work great) start the car and start tuning via a vacuum gauge. don't forget that you MUST adjust timing at the same time.

Plugs are actually dry and don't reek like gas :?

 

[megaladon6]

and it won't start on spray? interesting!

 

[megaladon6]

what's the timing set to?

 

[Bonnewagon]

It may still be flooding, as when you "put the pedal to the floor" what you are doing is activating the choke unloader. When the linkage is at the end of it's travel, it forces the choke open, letting fresh air in to lean out the flooded condition. Minor flooding would cause a hard start, and "run great" until the flooding overwhelms the carb. Could be the nitrophyl float is absorbing fuel, or the float level was set too high to begin with. A rich carb runs way better than a lean carb. As for the choke itself, why not swap in an electric choke? It's much simpler and reliable.