filter on carb?

[kelseydum]

I've been having this kind of bog/shutter when I take a slow turn and gun it and when I go up a steep hill. There are several other threads here stating the things I've done thus far and have narrowed it down to vacuum or fuel pressure issues... or I've got some valves sticking in the tranny.

I just thought about the fact that the carb is old and used (1982 Q-Jet). I pulled the carb filter out and it was nasty. I already have an in-line filter, do I need to replace the filter in the carb or can I leave it out? Also, could this be causing this bog.

Thanks,
Kelsey

 

[bob w]

I leave them out when using an in-line filter.

 

[Sniper]

Two or three things come into play with the Q Jet series carbs. First, yes a partially plugged filter may cause some hesitation or bog, but it would also cause a mid to high range miss. Generally one will show up with the other. Second the fuel filter itself, is there a rubber or soft plastic check valve it the end of it. The check valve allows fuel into the carb, but stops it from siphoning out when the vehicle sits for awhile. Ever have a GM that cranks over a number of times before it fires? Quite often the carb fuel filter/check valve is missing.

Provided both filters are clean, (carb and inline) they won't cause any grief if your running both. I would be more inclined to take a look at the accelerator pump that is in the carb itself. Some of the older pump skirts won't take a dose of alcohol laden fuel. they swell up and stick in the bore. Also check the delivery of the fuel, should see a strong stream of fuel when you look down the carb and work the throttle to the wide open position. You can do this when it's not running, that way you won't have it backfire into your face. The crystal ball can be a bit foggy at this distance, but that's where I would start.

 

[kelseydum]

thanks. It's idling great now (in near freezing weather).

This mostly happens when the motor has warmed up so not sure how to check the fuel stream. I've been burned before (random other incident).

I also noticed the distributor vacuum was hooked up to a port with no vacuum. Switched it to one with vacuum and maybe that will help???

 

[Sam_Fear]

Do you need to choke it when it's cold, or pump the acc. pedal once or twice before starting when cold? I mean 40 degrees or less cold. You might be getting to much fuel.

Not all vacuum ports are the same. You need to make sure your dist. is hooked to the right port or it can advance the spark too early or constantly, etc.

 

[Hydrocarbon Rocket]

You don't need the spark advance hooked to a port with vacuum at idle. It should only be vacuum as the throttle starts to progess open.