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post #1 of (permalink) Old 12-21-2000, 10:07 PM
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New Weber Carb Owner\'s tuning question

Here's a challenge for you Weber 32/36 owners out there, have any of you had to replace the idle jets that came with the carb?

According to the tuning instructions, I'm supposed to get "lean best idle" somewhere between 2 and 3 CCW screw turns (backed out) on the mixture screw, assuming the idle speed screw is no more than 2 turns in from contact with the throttle lever.

Well, my lean best idle is at mixture screw 3.5 turns out! The instructions say that anything more than 2.5 turns out means the idle jet is too lean (too small). Idle speed screw is right at 2 turns in. Am I the only one to have this problem? I thought the Weber kit was pretty much plug-and-play for the 258 engine, so I'm surprised I'm seeing this given I have the same engine everybody else has and I haven't seen this problem mentioned on the BBS yet.

Any advice on what I'm doing wrong? Or do I just need to replace the idle jets for bigger ones?

Thanks in advance,
DesertRat



90 YJ, 258 I6. Weber 32/36, the rest is stock Sahara edition.
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post #2 of (permalink) Old 12-22-2000, 09:00 AM
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Re: New Weber Carb Owner\'s tuning question

But, does it idle OK and/or does it bog right off the line. If it idles OK and doesn't bog I would leave it as is.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
Vice-Pres. Rock Garden 4 Wheelers, Farmington, NM
post #3 of (permalink) Old 12-22-2000, 07:09 PM
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Re: New Weber Carb Owner\'s tuning question

It idles ok in some circumstances, but not so well in others. If the engine is cold and I set the fast-idle cam and crank it then it idles fine at ~1500 RPM. But if I tap the accelerator to disengage the fast idle,or start driving, it drops down to about ~600 RPM at idle, and really struggles. Engine shakes so much that it shakes the PCV valve out of its grommet. Once the engine warms up though, it will run at the ~800 I set it to. If the engine is already warm when I start it, it will idle at the ~800 right away.

It seems I have three idle speeds rather than the two I can control with the screws: 1) fast idle at 1500, 2) curb idle at 800, and then 3) the crappy idle at ~600 if the engine is cold and it's not on the fast cam. I'd rather just have the two (800 and 1500) regardless of the engine temp! Could this be a function of automatic choke adjustment? If so, any idea how can I correct it?

Not sure what you mean by bogging, Brad, but it runs and accelerates fine when I step on the gas. Definitely a hp increase with this new carb!

Thanks Again

90 YJ, 258 I6. Weber 32/36, the rest is stock Sahara.
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post #4 of (permalink) Old 12-22-2000, 07:20 PM
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Re: New Weber Carb Owner\'s tuning question

The reason you will notice a poor idle for a few minutes when off the choke cam is because the Weber is VERY cold blooded. You no longer have the heated air from the manifold, it is just a fact that a warmer gas/air mix vaporizes better than cold.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
Vice-Pres. Rock Garden 4 Wheelers, Farmington, NM
post #5 of (permalink) Old 12-22-2000, 09:35 PM
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Re: New Weber Carb Owner\'s tuning question

Hey Rat....
Do you have a copy of the tuning instructions? I just bought a 32/36 from the BostonMangler and I am sure I will have to tune it. Could you e-mail me a copy or point me to some on-line instructions.

Thanks,
Tom

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post #6 of (permalink) Old 12-23-2000, 12:25 AM
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Re: New Weber Carb Owner\'s tuning question

Tom,
If all you need is the Weber 32/36 tuning instructions, that's an easy fix. I just happened to be looking at a site yesterday and found them, word-for-word what I got with the kit. Look at http://www.racetep.com/weber.html and click on the tuning link.
If you need more info than that let me know (like the installation info). Might not be as easy as the above, but I'll get you whatever I have if you need it (email, fax, whatever). Let me know.

//
Thanks for the answer, Brad. I'd buy that cold-air theory except that I live in Hawaii and the air is anything but cold right now. Even in the morning it's above 70, so I don't think air temp should be a factor (?).

Mele Kalikimaka
DesertRat

90 YJ, 258 I6. Weber 32/36, the rest is stock Sahara.
post #7 of (permalink) Old 12-23-2000, 10:26 AM
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Re: New Weber Carb Owner\'s tuning question

That's the only logical explanation, mine does the same thing, even in the summer here in NM. I believe the Weber is just VERY cold blooded. One thing that makes me think this is correct is in the winter if I drive along at highway speed for a while and then stop, it won't idle correctly for a few minutes.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
Vice-Pres. Rock Garden 4 Wheelers, Farmington, NM
post #8 of (permalink) Old 12-23-2000, 11:22 AM
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Re: New Weber Carb Owner\'s tuning question

Thanks. I'll keep tinkering with it, and if I ever come across a fix I'll be sure to post it.


Merry Christmas to all, and to all good jeepin'.

DesertRat

90 YJ, 258 I6. Weber 32/36, the rest is stock Sahara.
post #9 of (permalink) Old 12-26-2000, 09:04 PM
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Re: New Weber Carb Owner\'s tuning question

Desert Rat-
When I first installed my Weber back in May, I had a similar problem with getting to to tune right, so I called the Redline tech line. First, with the engine off, make sure that the linkage doesn't bind when the throttle should be all the way closed, and make sure that the secondary jet kickdown will open at wide open throttle. The techline told me that having the idle speed screw in too much when you adjust the mixture will create a small jet. Therefore, you might want to try, if it will idle, starting with the idle speed screw at 1 1/2 turns from the contact point and the mixture screw 2 turns out. Then go in first (rich), till it drops RPM a little, then back out to the best lean idle. Then turn the idle speed screw back in until you get the desired idling rpm. I don't have a curb idle solenoid on mine, so I didn't have to worry about that. I go from ~1200 RPM cold fast idle back down to ~500 RPM after I kick the choke off and it idles fine at altitude and 20 degree temperatures (Denver, CO).
It's a great carb (vast improvement over the BBD), but it's also a strange setup. Hope you get the most of your Weber.

post #10 of (permalink) Old 12-27-2000, 01:50 AM
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Re: New Weber Carb Owner\'s tuning question

Mele Kalikimaka Desert Rat, I don't know how much help I can be, but I run a 32/36 on my CJ5 and a dual 40 in my Toy. I have a few jets from when I set mine up on the Jeep that you are welcome to try. Let me know if I can help.I'm on the North shore (Wahiawa, Scofield)E-mail me directly

Jon
84 Toy,86 Toy,73 CJ5,93 RM125
[email protected]
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