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Even More Engine Troubles

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garage gnome View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote garage gnome Quote  Post ReplyReply Direct Link To This Post Posted: 20 Apr. 2014 at 9:50pm
Scout, try very slowly, and I mean slowly, increasing the RPMs. It will die just above an idle. Or try holding it at a steady RPM just above an idle. I'll take a video and post  it to show what I'm talking about.
Nate
1953 3A, 1949 3A, 1947 2A, 1918 IHC Titan 10-20, 1905 IHC Famous, other hit n misses
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scoutpilot Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 1:25am
With the the understanding that every motor is different, and no two random WO's are exactly alike after 65 years of wear and corrosion, it should take only a small amount of adjustment of either the Idle Stop Screw and/or the Idle Mixture screw to raise the idle RPM just enough to clear any potential hesitation or stumble in a carb with no vacuum leaks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote garage gnome Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 1:00pm
We messed with all the adjustments and it would not go away. When we put my spare carb on, it fired right up and purred like a kitten with no change to any adjustments.
Nate
1953 3A, 1949 3A, 1947 2A, 1918 IHC Titan 10-20, 1905 IHC Famous, other hit n misses
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rrrrrrrrr9 Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 5:23pm
I have a video of the problem that I'll post when I get home this afternoon.
Erik
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rrrrrrrrr9 Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 7:08pm
Scoutpilot at 1:20 on the video you posted I hear and see the stumble, but you yanked the accelerator linkage before it died. In all of the videos you have posted of my carb you always yank on the accelerator, and never increase the throttle slowly. Look at my video again, at the end when the engine dies I haven't touched the ignition. The engine dies purely because the carb wouldn't supply enough gas for the engine to run. This, as best as Nate and I can figure, is because the vacuum drops to about 5 at that point with my carb so it doesn't pull any gas through the high-speed jet. With Nate's benchmark carb the engine pulled a steady 17 or so all throughout the rpm range, and the high-speed jet kicked in right where mine stumbles and dies. What you said about the vacuum dropping with the accelerator opened only applies at heavy load and wide open throttle, or when you stomp on the gas like in your video, not in the situation we tested where the rpm was increased very slowly. Pay close attention to the speed at which I increased the throttle.

Erik
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scoutpilot Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 8:18pm
Did you try driving it?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rrrrrrrrr9 Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2014 at 9:41pm
yes, and starting from stops I had to floor it to keep it from dying, and offroad it was almost undriveable.
Erik
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scoutpilot Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr. 2014 at 12:49am
As my road test was a completely different experience, I will offer you a complete refund of the monies you spent with me.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Carlsjeep Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr. 2014 at 3:43am
Hmm, this is turning into an interesting problem. 

Nate, did you try his carb on your Jeep?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 11acs Quote  Post ReplyReply Direct Link To This Post Posted: 23 Apr. 2014 at 1:23am
Just out of interest, when the carburetors were swapped and the problem went away, was the gasket swapped also? Was the carburetor well seated?
Victor



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Post Options Post Options   Thanks (0) Thanks(0)   Quote rrrrrrrrr9 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Apr. 2014 at 10:36pm
same gasket, also the bad carb was pulling 20+ vacuum at idle on my engine,so there wasn't a vacuum leak.
Erik
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Clone421 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr. 2014 at 12:17am
I'm no carburetor expert, but this is what I gleaned from reading the documentation on the Carter-WO carburetor.
http://mightymo.org/Proj_carter_wo_101.htm

When the throttle plate cracks open just slightly above idle, thus uncovering the idle port, which the throttle plate is seated against when at idle, will supply additional fuel until the air velocity inside the venturi increases sufficiently to pull fuel through the high-speed circuit.

If the port is blocked the air/fuel mixture will lean out until the throttle is open wide enough to increase the air velocity inside the venturi and pull fuel out the high-speed circuit.

Have you tried testing the carb with the choke out?


Edited by Clone421 - 24 Apr. 2014 at 12:19am
Kyle
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SlowPocono Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr. 2014 at 1:21am
How about a stuck float from banging around during shipping?

And then, say that backwards when it's returned to the re-builder.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote daddyo4 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep. 2015 at 11:09pm
So did you find the problem? Mine was rebuilt last year and has less than 100 miles on it and I'm having this same problem. Idles fine but won't run up through the rpm's unless you jerk the throttle open to get it into the high speed circut. I've blown out all the passages and jets and everthinges seems clear. Anxious to hear what you found.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scoutpilot Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep. 2015 at 11:29pm
Try raising the metering rod about 1/32".
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Post Options Post Options   Thanks (0) Thanks(0)   Quote autolite Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2015 at 5:05pm
If your carb was rebuilt using one of those available repop 'master" kits, maybe the metering rod and or jet in the kit was not machined correctly. Just a thought. This is just my thinking, but if I had a spare that worked, I would remove each jet, one at a time from the bad carb and replace with jet from working one till hopefully, the culprit would reveal itself. Just a shade mechanic talking here.   
willys jeep
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stude-a-willys Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2015 at 6:04pm
My studebaker engine did this. It also had a lean surge at cruise (basically everything is different, but hold on a second here. Stay with me...) If I choked it a bit, it doesn't lean out and stumble on cracking the throttle. 

Gotta idea on two variables from Scoutpilot's mule motor and yours. Fuel and Elevation.

10% Ethanol fuel vs non-ethanol fuel makes a difference in the way my bucket runs. It runs a bit leaner with ethanol in the fuel. Any chance you have ethanol fuel and scoutpilot has "non-ethanol" fuel? what about adjusting for altitude? Makes a difference up here at 8900'. Not sure that Scout's mule motor and your rig are at wildly different elevations, but maybe a factor.




 


Edited by stude-a-willys - 14 Sep. 2015 at 6:10pm
Studebaker re-powered CJ2a
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oilleaker1 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2015 at 6:43pm
If it runs one Jeep, it should run yours too. You must have a fuel pressure/volume problem. Have you checked how much flow you have into a can or catch bottle? You can have pressure, but no volume. I just went through this with my M38. Drove me nuts like you are experiencing. John
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