LUVTruck.com

I just got a rebuilt Weber carb and I can't get it too run very good. It shows a lot of black smoke idling and accelerating, haven't moved it yet so I'm not sure about cruising. When I adjust the idle air mixture screw the tighter it is, the better it runs, but the screw stops turning before it stops pouring out black smoke.

My question is: What size jets are we supposed to have on our trucks?

The guy that rebuilt the carb said that the numbers 170 and 165 were on the jets, but I don't know if that's the size or what. Any info from you weber guys would be sweet. Thanks.

P.S. My truck has been broke down since July 25th. There are people I work with who have never seen my truck, and I would love to change that!

P.P.S. I've had a 3 inch body lift kit since it broke down that I want to install, but not until I know I can fix the truck so the sooner it runs the sooner I can put that on too. Thanks.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

those are definitly way too big... i think those are the jet numbers for a v-6 jeep application.

redline has a jet set you can buy for the luv setup ,they're really easy to change yourself.....and you can do that on the truck too.

BTW...my mains are #150 and the pump is #50 ...i don't have them written down at the moment.

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Well, considering I'm probably a couple thousand feet higher in elevation I should have even smaller jets than you to make up for the low level of oxygen in the air this high up. Do you know where I can get jets more suited for my application?

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

BTW, thanks for the reply, I was starting to wonder if anyone even knew what the hell I was talking about.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

no problemo.... i don't live on the sunny california coast though...i live in the sierra nevada mtns. so my carb is set to 5500ft

i got a set of performance jets from carbs.net they do a total setup for elevation, driving style and type of engine so it woorks right... it also costs the same as a standart jet set.

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oops... i have the page i ordered the jet kit from right herehttp://www.racetep.com/weber.html?src=overture&keyword=weber%20carbs#jets

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Allright, I went out with my little diagram and looked up the numbers of all the calibrated parts on my weber, (took about 3 minutes), and here's what I've come up with.

Needle Valve :........................ 250 (parts list doesn't show this as a calibrated part, but on the list the number is 200 and it's 250 on the carb.)

Primary Main Jet:.................... 140

Secondary Main Jet:............... 140

Primary Idle Jet:....................... 45

Secondary Idle Jet:.................. 50

Primary Air Corrector Jet:........ 160

Secondary Air Corrector Jet:... 175

And another description of my problem: I've had it started and idling for about ten minutes at a time in my garage. Not driven. When I start it up I tighten down the idle mixture screw all the way, because it does help the idle a bit, and it still is pumping out black smoke and even more when I rev the gas, and I wouldn't say it idles so much as it struggles to keep running. No flat spots and very little stumble if any, except the already rough idle. I haven't even tried setting the idle speed yet, cause I don't have a tach so I would have to set it by ear anyway, and I can tighten the speed screw all the way and it still seems to be idling really slow, probably cause of the mixture problem. Thank you much for help.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

those don't seem too out of line to tell the truth.

it almost sounds like the float isn't set right. pull the top of the carb off and set the float. the proper dimention is 42 mm. that's when the upper body is on edge with the float hinge up and the needle closed but not depressed.


call racetep and get the jet numbers so you can compare them. let's see if somebody(member) has a refrence chart or tuning book for webers.[/url]

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Hmm, it seems a little late, but with the drama goin' on right now, (refer to the lounge for further information) I might just go out and try to adjust it til everything settles down again.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

Mine seems to be set around 45 mm. You think that could cause it to overflow? Or underfill the bowel?

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

It's at 41 when you depress the ball in the needle valve. But the way I'm looking at it, the float should be shutting it down early, just the opposite of over-flowing.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

he he, padding the old thread count while I'm at it, used to think I was above that.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

ok that sounds like it's flooding a bit....it needs to be between 42 and 48 mm with the ball NOT depressed.the bowl is overfilling and riunning a bit rich...

Altitude wise id say to set the float torwards the top end of the range about 46mm. or so.

or another note, did you get the idle cutoff switch on the weber?
how did you set the choke?

here's the $1000000 question... who rebuilt the carb?

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BTW......do you still have the pup?......sorry...felt like padding too.

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Well, t he floats already at 45 so I don't see a big difference there, I'm not sure exactly how I'm supposed to set the choke and I don't think I have an idle cut-off switch, but I'm not sure what you're talking about so I couldn't say for sure. The guy who rebuilt is a friend of mine from work, says he knows alot about carburators and I don't think he's the boastful type.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

I took it for a drive and it goes down the road just fine, besides smoking alot. It's got at least as much power as it used to, but it's smoking all the time and it idles like CRAP.

When I look into the carb after driving the secondary bore was all wet with gas, ( I think cause the accelerator pump pumps into both bores equally, whether they're both open or not).

It's leaking gas from between the brass fuel inlet and the carb cause it's too tight against the thermostat housing. I have the idle mixture screw tightened all the way down cause it seems to run better there. But it will run if I take it all the way out, just not very well.

The bowl is set to 45mm and I've already got all the jet sizes listed. This sound like a fuel level problem, or just jetted too big. And if it's jetted too big, does anyone know what the right jetting is for my altitude?

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

if you can turn the idle mixture screw all the way down and it doesn't die then the carb is defenitly jetted too rich. no doubt about it. costs about $50.

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I noticed that the pump jet, (thing that squirts gas), has a nozzle for each bore, but since my carb is progressive, the secondary is pinched off, but where it was pinched, it's cracked and spraying gas into the secondary bore. One reason for the richness I guess, but still doesn't account for black smoke at idle. I called up the number on that site you gave me and they will sell me the kit, but I want to make sure they're not the same jets I have now before I spend another $50 I don't have and they refuse to give me the part numbers.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/

im having the same problem with my weber. i got the truck for my 17th b-day and mine smokes so bad. havent gotten it on the road yet, btw where is the idle air mix screw at? i have looked all over the carb for it. chilton's book said it had a cap you had to pull and i cant find it. any help?

It's at an angle in the bottom of the carb. It points back and toward the fender. I still haven't fixed mine though, so besides checking to see if the pump jet is broken like mine is, I couln't help ya.

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Richard Barnes Salt Lake, Utah
1980 Luv Mikado 4X4
http://geocities.com/luvtruck2004/