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Offline DavidB

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WO carb issue
« on: May 19, 2018, 08:45:24 PM »
Just rebuilt my carburetor, and cannot keep engine running unless choke is fully closed. I have correct pump travel and have set metering rod adjustment with the correct tool. I've also tried the propane torch , checking for leaks, but that didn't help or  change performance...Iam at a loss. Any ideas out there? I appreciate any and all advice.
« Last Edit: May 19, 2018, 08:50:44 PM by rufus39 »

Offline athawk11

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Re: WO carb issue
« Reply #1 on: May 19, 2018, 10:30:51 PM »
If you have to run with it choked, you might have a vacuum leak or the Carter might have some debris caught in a jet. 

Vacuum leaks can happen around the throttle shaft, the base of the Carter, and even at the intake manifold where it's bolted to the engine. 

Is there a difference in performance when idling or at high speed?  If so, this might help troubleshoot what might be clogged up.
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Offline DavidB

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Re: WO carb issue
« Reply #2 on: May 20, 2018, 07:53:53 AM »
Yes, there is a difference between idling and  increased throttle. It runs better with increased throttle, but the choke still must be fully closed.I had checked for vacuum leaks using the propane method I had read online about, but didn't notice any change.
Thanks for your input, I do appreciate it.

Offline mtnman37879

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Re: WO carb issue
« Reply #3 on: May 20, 2018, 08:30:37 AM »
I have found that if an engine must have the choke on to run, It needs a valve job.
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Offline athawk11

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Re: WO carb issue
« Reply #4 on: May 20, 2018, 05:36:30 PM »
Think about this in the most simple terms.  A carburetor is creating an air and fuel mixture that is optimal to be burned by the spark at the plug in the compression chamber. 

If you are forced to cut off the amount of air, (choke) ...then there is already too much air mixing in the chamber.  Thus why folks suggest trying to find a source where extra air is sneaking in.

Or, the amount of air is fine, but there is not enough fuel to reach the optimum fuel/air mix. A possible clog in the fuel delivery system.  This can happen at the tank.  The fuel pump and fuel lines...or in the carburetor itself.




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Offline DavidB

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Re: WO carb issue
« Reply #5 on: May 20, 2018, 06:33:17 PM »
Athawk11,
I have confirmed that I am getting plenty of fuel up to the carburetor, so, I want to believe that my problem is within the carburetor itself. It seems like I am getting plenty of fuel down the carburetor when I actuate the throttle linkage, as I see a good stream of gas when doing this. So, which jet(s) should I check for obstructions?

Offline mtnman37879

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Re: WO carb issue
« Reply #6 on: May 20, 2018, 09:02:44 PM »
When was the last valve job? The engine must make enough suction to get the fuel into the cylinder. Leaky valves stop the suction.
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Offline athawk11

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Re: WO carb issue
« Reply #7 on: May 20, 2018, 10:39:47 PM »
I do agree that an engine needs decent compression and vacuum to run well.

I'm simply looking at different issues based on past experience with the L-134 engine.  With only marginal compression (70s) and low vacuum (15 at 5,500' altitude), I have been able to get them to idle and run with zero choke.
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Offline athawk11

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Re: WO carb issue
« Reply #8 on: May 20, 2018, 10:54:30 PM »
Dave, I would probably start with the idle jet.  It's the long skinny one.  These are prone to clogs if the fuel supply isn't clean and filtered.  I've had to clean one out on the trail a couple years ago.

Also, there is an overlooked passage way between the idle mixture screw port and the chamber behind the large plug on the front of the carb base.  This can clog too, and is difficult to clean if the plug isn't removed.  It can cause problems with carburetor function.
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Offline scoutpilot

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Re: WO carb issue
« Reply #9 on: May 21, 2018, 05:53:01 AM »
Does the jeep have vacuum wipers or any other vacuum operated device? Check the supply tube(s) for proper fitment and/or any breaks.
Have you checked vacuum readings? What is your best idle RPM? If 900 and above, you may not notice a change in the motor with a volatile test, especially at altitude.
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Offline DavidB

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Re: WO carb issue
« Reply #10 on: May 23, 2018, 05:34:32 PM »
Ok, here's the update..I have rechecked every jet, all were clear. I even changed bases, but it still doesn't run unless the choke is near fully closed. Does anyone have a well , clear picture of all phases of the rebuild on the carburetor? The ones I have are too grainy to make sure I have everything as it should be. I am also going to do a compression test. What numbers are acceptable on this ? I am almost ready to order a new Solex carburetor, but I want to keep it stock, if possible..if I had hair, I'd pull it out.

Offline athawk11

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Re: WO carb issue
« Reply #11 on: May 23, 2018, 08:16:13 PM »
Dave,
ScoutPilot is our resident expert, rebuilder, restorer of the Carter-WOs along with other models.  He is more than happy to help you work through this by yourself, or rebuild it for you.  Exceptional work, and a pure business professional.

His web site is packed with detailed photos and videos.  If you don't find what you need, just post a question or send him a private message. 

http://oldjeepcarbs.freeforums.net

He can be found on every Willys site too.

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Offline DavidB

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Re: WO carb issue
« Reply #12 on: May 23, 2018, 08:30:10 PM »
Thanks so much for that . I will check it out.
I finally found time to pull a compression test..#1 -120lbs, #2=115lbs, #3- 120 lbs, #4--0--. So now I will remove the side cover and see if it's a stuck valve I suppose...I sure hope that is all it is, I am guessing that this is the answer to my carburetor woes?

Offline athawk11

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Re: WO carb issue
« Reply #13 on: May 23, 2018, 08:47:41 PM »
Ooooh.  Most surely a problem.  --0--?  Sure sounds like a stuck valve.  I was able to free up a stuck valve without pulling the head.  Mix up some Acetone and ATF  50:50.  Pull the side cover and the #4 plug.  Squirt some through the spark hole and wait. Squirt and wait. Squirt and wait.  Use a rod to gently push down on the valve.  Use a paint scraper, knife.  Work it between the tappet and bottom of valve stem.  Keep working it back and forth this way. Keep squirting the above mixture.  Eventually, the valve will be free.
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Offline mtnman37879

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Re: WO carb issue
« Reply #14 on: May 24, 2018, 09:21:16 AM »
If the valve was stuck the rattle would be loud. Time to lap your valves and hope you don't need to grind them.
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