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Old 10-02-2011, 04:17 PM
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slukev slukev is offline
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PO capped power valve vacuum line

I have another question for you guys/gals- Thanks- you are all helping me get the rig in a lot better shape! And I am learning a ton.

This is my first carb and first major project vehicle.
I rebuilt the carb on my 90 GW and found that the previous owner had capped the vacuum line going to the power valve on the carb.
When I reattached it, it caused a problem. I have a sloped driveway-When I put the rig into drive and hit the gas try to go up the driveway the jeep either dies or almost dies- going almost no where. No matter how slow or fast when I hit the incline it dies. I re-capped the vacuum line to the power valve and it has no problems, just seems to run a little rich.
I drove it for about 10 minutes with the line capped no problems running.

Any thoughts on the reason I have this issue? Should I leave well enough alone? I assume this is making me run rich....

Thanks again,
Kevin
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Old 10-02-2011, 04:22 PM
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power valve is blown.time for a rebuild.
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Old 10-02-2011, 04:26 PM
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I just changed the power valve during the rebuild- how likely is it that the brand new one is shot?
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Old 10-02-2011, 04:38 PM
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did you hook up a vac line to it or leave it open.vac holds it closed.if left open the valve will be open
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85 gw 215k and still going
castrated(de-wooded)360 2" espo springs 31x10.5
89 gw,free,almost legal

She can dance a Cajun rhythm,Jump like a Willys in four wheel drive,

the world is full of kings and queens who blind your eyes and steal your dreams

"Our militarized "law enforcement" has become the standing army our founders feared"
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Old 10-02-2011, 04:45 PM
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slukev slukev is offline
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If you mean-When I put the carb together I did not have it under vacuum...If I needed to it looks like I missed that in my instructions...And I just re-read them and don't see anything about that- I'll take at look as Ristow's instructions-his make good sense.

But currently I have it capped with no vacuum. When I hook up the vacuum that is when it dies.
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Old 10-02-2011, 06:03 PM
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Rich88 Rich88 is offline
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Quote:
Originally Posted by slukev
If you mean-When I put the carb together I did not have it under vacuum...If I needed to it looks like I missed that in my instructions...And I just re-read them and don't see anything about that- I'll take at look as Ristow's instructions-his make good sense.

But currently I have it capped with no vacuum. When I hook up the vacuum that is when it dies.

The purpose of the PV is to allow extra gas to flow by bypassing the regular jets when the engine is under extra load, like going up hill or passing. This is detected by low vacuum. Under light or no load conditions the vacuum is high.
High vacuum holds the PV off. If there's no vacuum to it, it thinks the engine is under load, and the PV open.

You probably have the carb adjusted to idle with the PV operating. Connect vacuum to the PV and retune the carb to idle properly with it connected.
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Old 10-02-2011, 08:43 PM
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What carb is it?
2100's and 2150's get their PV vacuum from under the carb, not through an external line.
The vac nipple under the driver's side idle adjuster was probably capped because the PO unhooked some of the vac equipment before you got the waggy and capped that nipple to prevent a vac leak like someone did mine.
If that's the case, then your engine needs that cap to run right as it does now.
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Old 10-02-2011, 09:20 PM
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talntar talntar is offline
 
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Quote:
Originally Posted by Rod2
What carb is it?
2100's and 2150's get their PV vacuum from under the carb, not through an external line.
The vac nipple under the driver's side idle adjuster was probably capped because the PO unhooked some of the vac equipment before you got the waggy and capped that nipple to prevent a vac leak like someone did mine.
If that's the case, then your engine needs that cap to run right as it does now.

not completly true.early 2100 and 2150 got there vac from undernieth.later ones had external vac.i have 2 of each here.
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85 gw 215k and still going
castrated(de-wooded)360 2" espo springs 31x10.5
89 gw,free,almost legal

She can dance a Cajun rhythm,Jump like a Willys in four wheel drive,

the world is full of kings and queens who blind your eyes and steal your dreams

"Our militarized "law enforcement" has become the standing army our founders feared"
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Old 10-03-2011, 08:39 AM
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talntar is correct, although I'm not sure when they switched, the 2150 on my 87 GW gets the vacuum signal for the power valve from an external vac line.

I'm planning to rebuild my carb this week if I have time, because my power valve is bad. As a "stop-gap", I capped the vac line to keep fuel from spilling out onto the intake. As someone mentioned, doing this causes the power valve to be on/open all the time, which will make the engine run rich.

To slukev, assuming your power valve is still good(no fuel coming out of the vac nipple), you'll need to reconnect the vacuum, and then readjust the idle mixture screws.
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Old 10-03-2011, 10:49 AM
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I haven't been able to re-adjust it yet, but now that I know how the power valve works I am pretty sure I'll just need to adjust the mixture for a functional power valve (under vacuum). And first I want to get some new vac line as the existing one is in rough shape and may be on its last leg anyway (I just need to buy those lines in bulk...but almost have them all replaced).

And Muddy- you are correct nothing is leaking out of vacuum nipple.
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  #11  
Old 10-03-2011, 10:39 PM
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Quote:
Originally Posted by talntar
not completly true.early 2100 and 2150 got there vac from undernieth.later ones had external vac.i have 2 of each here.
Thanks for the correction. You can tell by my sig line that mine is an earlier one.
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