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glacier
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Joined: Jan 18, 2012
Posts: 6
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 Posted: Sat Jan 21, 2012 10:57 am Post subject: Sticky gas pedal |
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I have a 1952 m38 that's been in the family a while and I recently took over ownership. Last year the gas pedal started 'sticking' periodically. It normally happened during start up, but i could hit the pedal from the side and it would come back up and be fine for the rest of the drive. This started happening more and more frequently. Now when I start the Jeep I make sure it is not pressed down, and keep my foot away from the gas pedal when I start. Immediately when I start up the gas pedal gets pressed down somehow, and I can't get it to come back up. I then have to shut off the jeep. I haven't been able to get the jeep out of the garage for the last few months because of this. The last few times I did this, I had a friend looking under the hood to see if he noticed anything off. The fuel pump started overflowing, possibly from getting too much gas? I desperately want to get this fixed, and am looking for any ideas/suggestions on why this is happening and what needs to be done to solve the problem. I should mention I'm a girl with limited car knowledge, so please keep that in mind with any explanations  |
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oilleaker1
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Joined: May 14, 2009
Posts: 972
Location: South Dakota
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| Posted: Sat Jan 21, 2012 4:33 pm Post subject: |
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Hi, you need to oil or lube all the moving points between the gas petal and the carburator. Also make sure the throttle return spring is connected. Any car savy friends should be able to help you. Now, your M38 is which model? The older flat hood or rounded in the front hood. They made two types that year. M38, and M38A1. We could have Wes give you detailed pictures if you know which model of Jeep you have.  John |
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Cacti_Ken
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Joined: Apr 20, 2005
Posts: 1021
Location: Silsbee, Texas
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| Posted: Sat Jan 21, 2012 8:46 pm Post subject: |
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The throttle return spring John is talking about is or should be connected to the throttle valve on the carburetor and the other end anchored at another point so that the valve will close when you take your foot off the pedal.
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wesk
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Joined: Apr 04, 2005
Posts: 16258
Location: Wisconsin
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| Posted: Sat Jan 21, 2012 11:24 pm Post subject: |
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The mysterious sucking down of the gas pedal on startup may be soft or torn motor mounts allowing the engine to rock left/right more then it should. If you do have the return spring hooked up and it still gets stuck then do a thorough inspection of all the moving parts.
Fuel pumps do not overflow but they can leak. If you see fuel coming out of the pump housing you need to repair or overhaul the pump. First check that the two fuel line fittings are tight in the pump and then check that the fuel side diaphragm housing screws are all tight.
1950 thru 52 M38 spring
1952 thru 1971 M38A1 and M170 spring
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Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php |
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jam51m38cdn
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Joined: Feb 06, 2008
Posts: 69
Location: Findlay, Ohio
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| Posted: Sun Jan 22, 2012 6:00 am Post subject: |
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People post on here from all over the world,more than likely someone in your area belongs to a military club or has a jeep like yours and would be glad to help you out, if you and your friend can`t figure it out. Jim  |
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AeroE
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Joined: Aug 31, 2008
Posts: 49
Location: SE MN
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| Posted: Sun Jan 22, 2012 5:06 pm Post subject: |
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| Wes: I’ve seen several pictures of what appears to be an NOS M38 engine that you’ve used to illustrate a point (as above). Are these pictures collected in one of your albums? I’d like to see all of them. Also, is it NOS and what’s the story? |
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wesk
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Posts: 16258
Location: Wisconsin
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AeroE
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Joined: Aug 31, 2008
Posts: 49
Location: SE MN
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| Posted: Mon Jan 23, 2012 12:01 am Post subject: |
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| Thanks-somehow missed that album. What did it go for? |
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wesk
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Location: Wisconsin
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RICKG
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Joined: Aug 31, 2010
Posts: 1741
Location: SO IDAHO
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| Posted: Mon Jan 23, 2012 12:00 pm Post subject: |
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Thx for the photo album Wes..
The "HOLY GRAIL" of engine finds..
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RICKG MC 51986 DOD 01-52, '50 CJ3a |
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swat
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Joined: Jan 27, 2010
Posts: 98
Location: Warner Robins, Georgia
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| Posted: Mon Jan 23, 2012 10:03 pm Post subject: |
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| What a treasure those Cadillac Fence Company photos are within themselves! |
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glacier
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Joined: Jan 18, 2012
Posts: 6
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| Posted: Mon Jan 23, 2012 10:07 pm Post subject: Update with photos |
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Ok, I took all the info you guys provided and did a little investigating tonight. First, we checked all the moving parts, and everything seems to be moving ok when the jeep is not running. Based on one of the comments, we lubed everything up and tried again. Without touching the gas pedal, it sucked down. On the second try, it started leaking where this photo below shows. I did notice the spring set up looks a little questionable. Not sure if that could be the cause, or if it is something else with the carb. Anyhow, I'm hoping these photos provide a little more information that might be useful in finding the solution. I do have a few more photos if this is not enough. Thanks so much for the replies!
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chicklin
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Joined: Jan 03, 2012
Posts: 48
Location: Kansas City, MO
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| Posted: Tue Jan 24, 2012 12:13 pm Post subject: |
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Is it me or does it look like the spring is pulling the throttle in towards the carb? i.e. opening up the throttle? I'm not familiar with the M38 carb/throttle setup, but it sure looks fishy in your pic.
About the only thing that would cause what you're describing is the spring pulling the wrong way or some sort of vacuum condition in the carb, but I doubt it could create enough vacuum to pull against a throttle return spring.
First thing I would do, at a minimum, is clean the heck out of that whole area so you can see what's going on. And your carb likely needs rebuilt or at least re-sealed.
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1953 M38A1 #55997 |
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bbloom
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Location: Kansas City
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wesk
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Joined: Apr 04, 2005
Posts: 16258
Location: Wisconsin
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| Posted: Tue Jan 24, 2012 8:08 pm Post subject: |
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Your spring is pretty darn close in length and location. I don't think it is your problem with the pedal moving to the floor when the engine starts. As I have already stated I believe the un-commanded pedal movement is a function of motion between the engine and jeep. Have you determined what condition the engine mount isolators (rubbers) are in?
As for the leak you point out. That is the bowl vent and should have a tube connecting it to the cross over pipe between the carb and the air cleaner. Leakage there indicates a very full bowl which is caused by a float malfunction. Usually a stuck inlet needle, leaky inlet needle, heavy float etc.
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Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php |
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