1987 Carb Issues
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1987 Carb Issues
Just purchased a 1987 motorhome with the460 4bbl. Carb was rebuilt as was running too rich for emmisions. Included in the rebuild was the economizer valve. Now when you accelerate, there is a flat spot where the engine will die, it is ok if you "stomp it" past that point? Also is idling rough. Will be doing a full tune-up this weekend. Any ideas?
Thanks
1987 E-350 MH
1991 F-350 C/C DRW
Thanks
1987 E-350 MH
1991 F-350 C/C DRW
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Joined: Dec 2001
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From: Louisville,Ky.
Hi and welcome to FTE 
What type of carb is on it. Is it a Holley?
It sounds like an accelerator pump adjustment is needed.
Do the tune up first. Be sure to check and set the timing as needed. Then try running it again. I would also check for vacuum leaks too. Line off, base gasket not sealing?
Jimmy
What type of carb is on it. Is it a Holley?
It sounds like an accelerator pump adjustment is needed.
Do the tune up first. Be sure to check and set the timing as needed. Then try running it again. I would also check for vacuum leaks too. Line off, base gasket not sealing?
Jimmy
Last edited by LxMan1; Oct 13, 2003 at 11:46 PM.
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An economizer valve sounds like a power valve with a lower opening point. So, instead of it opening when the motor needs it, it opens later and thus you have the flat spot. Most truck motors using the Holley carb had a two stage power valve. It provided additional fuel on a two step basis and more closely matched the demands of a motor pulling various amounts of weight. So find out what power valve they installed when it was rebuilt.
Mark
Mark
5th Wheeling
Joined: Oct 2003
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From: SE Mass
I have an 87 MH with same setup (460CID & Holley 4180). I rebuilt carb using a Jiffy kit and it turned out that power valve supplied with kit was economizer and caused problems you are describing. I replaced it with 2 stage valve (I think p/n was 25R609-8A) and it solved the problem.
I'm not real happy with the performance of the Holley - it runs ok after I rebuild it - but then after a while starts acting up again. I'm looking at either replacing it with a Carter AFB - of one of the TBI systems now available from Holley
I'm not real happy with the performance of the Holley - it runs ok after I rebuild it - but then after a while starts acting up again. I'm looking at either replacing it with a Carter AFB - of one of the TBI systems now available from Holley
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1987 - 1996 F150 & Larger F-Series Trucks
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