1984 Jeep CJ-7 Progress 2013 05 20

Click Picture or Text for more pictures / details

It has been awhile since I worked on the Jeep. I have been very distracted trying to understand the blower and mechanical fuel injection on the dragster. The Jeep has been great around town, but above 45 MPH, it is pretty dead. On the expressway at 55 MPH when you hit a hill. it loses ground.

I have not been happy with the amount of fiddling around I have seen required to make the Weber carburator work correctly (according to contributors on the Jeep Forum).

I finally got to a point where I wanted to do something about it and was given a name and contact that was in the know. After some discussion, it was decided to pull the 32/36 off the Jeep and replace it with a 38

A 38 was purchased and my expert had me install .50MM idle Jets, 1.45 MM Main Jets, 1.70 MM Air Corrector Jets, f& Emulsion Tubes, Vitro tip needle valve

	So this is what we started with, AMC ignition box and computer are gone, MSA box has replaced it with the stock distributor and coil. So basically a stock set up.
	This 32/36 was purchased with the the O.E. air filter ADAPTOR 99010.600 so that the stock air filter could be used.
	Here they are side by side, note the throttle linkage is different and the 38 has studs for the Weber air filter. Also note the straight mechanical linkage on the 38. Swapping the throttle linkage was very simple as I had followed the instruction when it was installed so it came apart very easily
	Next was the studs on the new 38. they had to be removed and the holes drilled and taped to accept the larger bolts for the air filter adapter. Again not a big thing so long as you have the correct metric tap.
The next difference was there is only one vacuum port on the 38 while the 32/36 has two. One is delayed vacuum (not ported) and the other is not and was used for the vacuum to control the functions on the charcoal vapor canister. Again not a big thing I will just pick up the vacuum from the intake manifold for this purpose.Also note that the fuel inlet on the 38 is on the opposite side of the 32/36. A new fuel line will have to be made up. The fuel inlet on the 32 is threaded on both sides with a threaded plug in one and a screwed in fitting in the other. This allows you to switch them around how you like. The 38 comes with a pressed in fitting on one side and the other blocked off. I did not want to remove the top of the carb pull out the fitting, drill out the blocked off side, thread both sides, insert the plug on the side I did not want the inlet and move the inlet to the correct side before testing the application. I will do this once the Jeep is running correctly. I do not like the new fuel line running across the carburetor
Next problem was the bracket for the throttle cable linkage would not sit down on the base because the barrel of the carburetor is bigger. A little grinding solved that problem

Test drove it with out any adjustments and it stalls at stop signs. Seems to rev better, but did not take it up on the expressway to check power above 45. Acceleration is not smooth, seems doggy in lower rpm then bogs down then picks up and goes pretty good.

With out adjustments I seem to have the opposite of what I had, with the 32/36, it was good on the lower end with lots of torque, but dead on the upper end, now with the 38/38 it stalls in the lower end, doggy down low but seems to pick up in the upper end.

I have been properly scolded for not adjusting it before test drive.

I spent some time adjusting.

I found that I could turn the idle speed screw in a 1/4 turn more before the vacuum registered on the delayed port. This allowed me to get the Jeep to idle without having to hold the peddle.

I checked the timing and found that it was at a static 6 degrees, bumped it up to 8 and then had to reduce the idle speed screw by almost a half turn to get the idle down to 500. There is zero vacuum at the delay port and I can screw the idle speed screw out and 1/8 of a turn before vacuum is registered on the gauge. So the idle screw is now 1/8 in before vacuum registers (every expert makes a big point on this).

INTERESTING point, the delayed port only develops 15 pounds of vacuum, while the manifold vacuum is close to 20. I’m wondering if I am getting full vacuum advance with the reduced vacuum for the delay port on the carburetor.

 The 38 has adjustable low speed jets (32/36 does not), they were bench set at 1 1/2 turns, with an tachometer I found the “Best Lean Idle” by bracketing the fall off of RPM to be 1 1/4 turns out.

Test drove again, it does not stall, pulls pretty go, but not great, there is a small weak spot at about 1/3 throttle, seems to pull pretty good in the upper RPM 2,000 to 3,000 range. I am out of time and will have to try the highway tomorrow.

When I go back I added an additional 2 degrees in timing, now at 10.

Maybe this will remove the weak spot at 1/3 throttle????

More later.

Comments on the pictures below will follow at a later date.