View Full Version : Hesitation = Power Valve ?

12-27-2002, 05:02 AM
I have an 87 Grand Wagoneer and if i push the go pedal to the floor hard the motor with hesitate and stall unless i let off and apply the throttle gradually.

I have read other posts by people with similar problems and it is often suggested that the power valve is bad.

In my Haynes maunal what looks like the power valve shown on the advance auto web site is labeled as the "economizer valve".

Are the economizer valve and the power valve the same thing? And does my problem sound like a bad power valve? I have also seen some post mentioning problems with accelorator pumps, could that be the problem.

I appreciate your time and advice.


12-27-2002, 05:05 AM
a blown power valve is a very common problem with the Motorcraft 2100 series carbs. Sounds like you're looking in the right direction!!

I've never heard of an economizer valve....but I've never rebuilt a 2100 either...just got mad at the one on my 86 =)

12-27-2002, 05:07 AM
A bad accelerator pump diaphragm or power valve can can the symptoms you describe- puts a little too much fuel into the carb. Both can be replaced fairly easily.

12-27-2002, 05:13 AM
Welcome Dean!

I assume you have the stock 2150 motorcraft carb. First check the accelrator pump linkage. The pump is acually driven by a spring on the drivers side butterfly shaft that is released when you step on the throttle. The spring can get dry and stick. Spray it with some lube and work the throttle and make sure the pump linkage activates smoothly.

Next pull the vacuum line that goes to the power valve - it is on the front/center bottom of the carb. If any fuel drains out when you pull the vacuum line the valve is blown and needs to be replaced. Start up the engine and check for vacuum on that vacuum line. The econimizer and power valve are two different names for the same thing. Often if the power valve fails the truck will run rich as it will always be dumping fuel. Sounds more like your accelerator pump is the problem.


Don S
12-27-2002, 10:25 AM
Originally posted by DCD1278:
In my Haynes maunal what looks like the power valve shown on the advance auto web site is labeled as the "economizer valve".

I appreciate your time and advice.

... Welcome to the IFSJA group. I sure hope you enjoy our members here.
I agree with Red Dog and will and these helpful links

link> FSJ MC-2150 CARBURETOR (http://www.ifsja.org/tech/fuel/2150.shtml)
link> MC-2150 CARBURETOR (http://home.earthlink.net/~bubbaf250/2150carb/carb01.html)

… Below is a good fast link to acronyms we really use.
link> Acronym and Abbreviations for 4x4 Gearheads (http://groups.msn.com/NISSAN4X4TRAILS/acronymlist.msnw)

Happy Holidays and ..CUL… ds..
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1976 406 MC4300 TH400 QT TruTrac 2" lift 31x10.50s duel Optimas
It’s taken us over 261 Colorado Mountain Passes since 1985-
BRC#30093 link>Blue Ribbon Coalition JOIN save your TRAIL (http://www.sharetrails.org/)
http://www.fullsizejeeps.com/jeeps/files/1963-1983-Wagoneers/76snorL.jpgThe Jerry can is plumbed
link>2003 OURAY Invasion Info and High Altitude Tips (http://groups.msn.com/ATexasOklahomaJeepClub/ouraycotopic.msnw)
link> Acronym & Abbreviations for 4x4 Gearheads (http://groups.msn.com/NISSAN4X4TRAILS/acronymlist.msnw)

12-27-2002, 01:04 PM
Mine had same problem. Acc pump was dri rotted. Rebuilt carb. Removed all smog equipment on carb.
Dosen't stumble at all. Kit purchased from O'Riley store. Simple to install. Be sure to change your fuel filter. Also replaced "sock" in the gas tank and that ended the stall at cruising speed.

12-28-2002, 01:31 AM
Great link DonS, that Bubba's write up on the MC2150 is the best I've seen anywhere. It's been printed and cataloged already!