dirty carb (and plugs?)

Joined
Feb 9, 2002
Messages
1,190
Location
Utah
ok, i've been having trouble with the low end torque as some of you know.
i've got the gap at
gap.JPG


and the plugs all look like this
plug.JPG


and my carb gets grimey (after what might only be a trip to walmart and back)
carbdirt.JPG


and i clean it to look like this (carb cleaner)
carbclean.JPG


if i shorten the gap to .45 will that make the spark more potent?
i'm running the DUI.
what do you other DUI guys have your gap set at?
i'm also always getting black exaust all the time.
 
Joined
Feb 9, 2002
Messages
1,190
Location
Utah
ok, assuming that #1 is the plug closest to the radiator;

#1 is the plug in the pic,
#2 was black, very black
#3 was less brown than #1; i would call it tan
#4 was tan like #3
#5 was pretty brown
#6 was pretty brown too.

why would #2 be so black and not the others?

also:
when i stamp on the gas and hold it down, it tries to die... then i let off the gas at the last minute and the engine revives itself. (this is when in neutral of course)
 
Joined
Jul 5, 2003
Messages
1,995
Location
Central, Utah
I don't know about DUI but stock plug gap (per manual) is .040". Your plug color should be tan to light brown.
What carb is that? I thought you said you had a Q-jet. Sure doesn't look like a Quadra-jet to me. A Q-jet is a 4-barrel, spread bore.
 
Joined
Feb 9, 2002
Messages
1,190
Location
Utah
ok, i've gapped them all down to .45 to see what would happen.
all of my plugs then went black.
then engine would then lag even more when i hit the gas hard (in neutral).

now i've gapped them out to .55 and there is less lag when i stomp it in the before fashion. i think there is a little put put sound coming from the tail pipe, but the exaust smeels less rich.

should i go back to the .45 and lean out the carb, or should i stay with the .55 and lean it out less.

i think also at .55 it feels like there is slightly better torque.
now that i've blackened the plugs, do i need to go buy new ones or will it burn off?

yeah i was wrong about the carb too (i'm retarded)
it's a "GM 2 Jet Rochester" it says right on the top (duh)
 
Joined
Jul 5, 2003
Messages
1,995
Location
Central, Utah
To set your mixture first verify that ignition timing, dwell, and advance are correct. Then set idle at 690 RPM. Adjust mixture screw to achieve highest idle speed. Readjust idle speed screw back down to 690. Repeat adjustments until speed can no longer be increased by mixture screw. Reset idle speed screw to achieve 650 RPM.
 
Joined
Jul 5, 2003
Messages
1,995
Location
Central, Utah
Those are your mixture screws. They should be adjusted the same amount of turns out from bottomed. Your idle speed screw is the one on the side that cracks open the throttle.
 
Joined
Feb 9, 2002
Messages
1,190
Location
Utah
fooling with the mixture screw (either or both together) barely makes the engine change... anything.
this carb must be junk.
 
Joined
Feb 9, 2002
Messages
1,190
Location
Utah
i assume there is some kind of adapter.
i think i'm going to try the $13 rebuild kit first and see if that gets me anywhere.

if not, i'll get back to you on that offer.
 
Joined
Jan 3, 2003
Messages
7,184
Location
McCall, ID
Rochesters were common on FJ40s, for some reason. Don't know why, but I haven't heard anything especially good about them. I would get an AISIN, either new or used to rebuild.
 

Users who are viewing this thread

Top Bottom