Rebuilt carb and still not running right

[ranchhopper]

I just got the carter YF carb back from the rebuilders and still it stumbles and backfires at half throttle and above. I dont know whats next I really getting POed this jeep has been all redone and it still refuses to run right. The engine runs like a top when idleing an starts great but when it reaches a point it stops accelerating and falls on its face. It reminds me of a 1970s chevy truck with the vacuum advance hose left off the carb runs great to a certain point then stumbles and backfires Im at a loss on this one carbs have never been my strong point in working on engines.

[1955CJ-5]

Has the fuel pump been rebuilt? Others have had problems and traced it to the fuel pump, even when the pump had recently been gone through.

Change the fuel filter if you have one. And check the tank pickup tube to be sure it isn't partially blocked...

Hope you find the problem....

[Matto]

Any chance of swapping with a friends working Carter WO to see the differance?
The Carter YFs were used on F head motors.
Matt

[ranchhopper]

I have been over most of the possible problems so far maybe the weights in the distributor may be seized not letting the distributor advance thats my next place to look.

[garage gnome]

Some Lheads used the YFs, like the ones from the DJs.

It could be a Vacuum leak, worn distributor, or like you said, it isn't advancing. Have you checked the timing?

[ranchhopper]

No I was going to check the timing too I looked for a vacuum leak but found nothing out of the ordinary.

[scoutpilot]

If it is idling well, then you have no vacuum leak. I'm in the camp with the distributor problem. Gummed-up flyweights or worn posts they turn on, or springs that have lost their tension.

[ranchhopper]

I have gone over the whole thing on the jeep now what I have noticed is the distributor has been turned all the way to the end of its adjustment. I have a friend who thinks it is one tooth off a vacuum gauge tells me its timing is running retarded but there is no more adjustment to advance it. How does one go about setting the distributor one more tooth forward since there is no drive gear on the distributor shaft?

[athawk11]

RH,
� You are describing the exact same issue I was having.
� You have to pull the oil pump and move its gear a tooth.
 
 Which I must add, is a real pain in the rump on a fully assembled Willys.� I ended up pulling the exhaust pipe off the manifold.� This gave me a little more room, but it was still tight.�

I will add that once I was able to time the engine correctly, it ran like a fresh rebuild.

Tim

[ranchhopper]

Thanks Tim which way did you turn it I dont want to have to disassemble it again if I turn it the wrong way my distributor is turned all the way to the right the jam bolt is at the top of the adjustment slot on the back of the distributor.

[athawk11]

I was turned all the way to the right also.

It's been a while, but if memory serves, I turned it counter clock wise...peering down the distributor hole

or

Clock wise if you are looking up through the oil pump hole.

This is a helical gear on the oil pump.  The trick is to move it one tooth, (which I think represents about a 30 degree change) but the helical style gear will move when you re-insert it and it make contact with the gear on the camshaft.
Same thing when you pull it out.

I had a tendency to think I moved it one tooth, but it kept on ending up in the same place.  !%@$ helical gears!!!

Tim

[1955CJ-5]

This discussion got me thinking as my engine will go together soon...so looking in the service manual reprint that I have paragraph D-85 explains the install of the oil pump and the orientation of the distributor drive.

But my distributor does not have the adjustment limiting slot, just a pinch bolt, so theoretically I could rotate it 360 degrees...or so it seems...

Do I have the right adjuster? The Distributor is an IAD 4008.

[athawk11]

Randy,
You are correct. You have the original distributor set up.� RH and I do not.� Ours are likely replacement distributors for later Willys.� The mounting hole in your mounting bracket is a mounting and adjusting slot for me.
 
Here is a post at the 2A page while I was fighting this battle.� It may be helpful to you and Ranchhopper.� Pay particular attention to the responses from Sean.� He is the guru on L-134 engine timing.

http://www.thecj2apage.com/forums/per-faq-l134-ignition-timing-by-sean_topic26318_page1.html?KW=timing

Tim

[1955CJ-5]

Thanks Tim,

Very helpful link.moving the plug wires is definitely thinking "outside of the box"...

You guys must have something similar to the distributor on the CJ-5, with the adjusting collar fixed to the distributor and a slot for adjusting...

[athawk11]

I'm not familiar with the Disty on a CJ5.�
This was the best photo I could find of my current distributor. ( For some reason, I neglected to take close up photos of this side of my engine. )

What do you think?� CJ5 Distributor?

Tim