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cj7 258 Weber Tuning Issues

2K views 43 replies 6 participants last post by  Matt1981CJ7 
#1 ·
i recently purchases a weber 32/36 dgev from weber direct after i just rebuilt the motor. everything is brand new. I am wondering what jets i need to run in it to get it to run not so rich. it came with these jets:

Mains p/s 145/145
idle 75/60
air corrector 160/160

not sure on pump jet. also when i first start start the jeep in the morning is worms up really rough and chugs like it might be getting to much fuel? or maybe not enough? i am not sure. but once warm it runs great minus the smell of fuel.
 
#5 ·
So instead of the advance port on the carb use manifold? I am trying to get it to run with 0 vacuum from the S port and cant keep it idling. Not sure what to try next? I checked to make sure the plates were covering half of the progression port like in the thread and it js about 1 1/2- 1 3/4 turns on idle screw. With a 75 idle jet 2 turns out it wont stay running or have 0 vacuum
 
#6 ·
Yes, manifold vacuum. It's been said that you can pull up to an inch and a half of vacuum through the spark port on the carb and still be "good enough". That's a terribly small carb for a 258.


Shawn
 
#7 ·
so then plug off the vacuum advance and just run manifold full time? i didn't realize it would be such a pain to get this tuned right. i bought the carb back in june and still can't get it right. Im not sure if this has anything to do with my issue but on a parts list i received from weber it goes over the "original Specs" for the jetting and what not and from what i see everyone on here post with jet sizes its pretty much the same besides the air corrector jets. i see others with 170p/160s and mine came with 160p/160s could that be an issue? my main jets are both 145
 
#8 ·
That's correct, Bob. Plug the port on the carb and run the hose over to the manifold vacuum port below the carb on the drivers' side and keep it there.

I've never seen anyone correctly tune that carb with anything smaller than a 170 primary with 175 being more normal. A 160 on the primary side is probably never going to work.


Shawn
 
#10 ·
I'm really not a fan of the F-50 tubes that come installed but, being that there's such a large demand on the primary side, it might be ok. Personally, I would install an F6 in the primary side and see how it responded to a fairly rapid throttle opening and whether or not the midrange torque improved.

As for the secondary side, I'd definitely install an F7. A wide-band air/fuel monitor would be a God send at this point.


Shawn
 
#25 ·
Hey now, I was creaping through this post from the other day and this stood out to me.

Bob, did you disconect the vacuum advance hose, then set the timing to 12 degrees and then attach the manifold vacuum to the distributor?

If this wasn't the order you did this, and are running 12 degrees with the manifold vacuum, this would be retarded timing.

If this is true that may be the reason this Chinese clone won't idle.

The K551-38 using a real Weber will help this situation alot.

Just sayin....

UPTILLNOW :cheers:
 
#13 ·
Shoot. You might have to cheat up to 1.5 inches of vacuum at the spark port and see what happens. You're fighting a tiny carb, buddy.

If that doesn't do it, we can cheat a little more but you'll have to pull the carb off to do it.


Shawn
 
#15 ·
Ok so lets say i run the f7 secondary and f6 primary. What is differance in the f50 and f6? Also with running f6 would any other hets need to be switched so the combination of sizes worked together? I ask because ive actually been learning alot as i try different things and take this apart and see everything and get a good grasp how it all works. Now i am curious of different jetting setups so i might get an idea on good combo to try.


I just took all the jets and everything out and blew air thru the carb and all jets to see if maybe one was blocked. I blew ait thru the air fuel slot and now see how idle circuit works i felt air coming thru the hole. So maybe i should wait for the other air corrector jet so i have the right setup?
 
#16 ·
Unfortunately, the air correctors, mains and emulsion tubes are irrelevant at this point. If you're committed to this carb, I see two options: a) take the carb off and crack the secondary throttle plate open no more than a half a turn, or b), drill a 3/16th hole in the primary throttle plate.

Both of those moves will allow more air into the engine and hopefully let you close the primary throttle plate back down a little so you're not idling on the enrichment circuit. I don't think I'd worry too much about main jets and air correctors until you get the idle sorted out.

Pain in the neck, huh...


Shawn
 
#23 ·
That's your bigger problem right there. It isn't even a real Weber. Definitely go with a genuine Weber 38 from Redline. Try to hook up with Tom at 800-733-2277 ext. 7345. He'll get you taken care of!


Shawn
 
#27 ·
Ok so i got the actual weber 38. Using the jets that comes in it and not changing anything. What should the final screw settings be on both barrels for lean idle? I did acheive 0 vacuum or at least very very close. Maybe 1 but my gauge just shows 0 in white area the dash marks go 3,4,5 ect. And yes i got the timing at 12 without advance hooked up. Lets say i ran cac adv off carb. What would timing be then?
 
#30 ·
Without knowing what idle jets it was shipped with (hopefully not 45's) all I can really do is tell you what I've seen.

45's- 2+ turns out on the mixture screws and God help you unless you're up in the mountains.

50's- Should land somewhere around 1 3/4 out.

55's- Closer to 1 1/4 out

60's- About or perhaps under 1 turn out.

I'll also say this; although you get what appears to be a silky smooth idle with the larger jets, you'd be amazed at how rich they can run when off the idle circuit and into the enrichment circuit.

They can all be a little different due to a host of things so, by all means, test.

Shawn
 
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