Hiya, I've got a 38 on my pig. I was having some issues with it awhile ago and read up on some of known problems and solutions. the trouble shooting file is a good start. How does it act when it's warmed up and idling? If it does fine, it may be that the auto choke is sticking. It can be cleaned and adjusted. Here is a discussion I found over in a jeep forum for a weber choke:
When the motor is cold and off , pull the air filter off and observe the plates on the top of the carb,
they should be vertical. Then using the linkage, pump the gas once. Those plates should snap
shut. If not take a sharpie or other marker and locate the assembly off the carb on the left side as
you're looking at it from the front, it has three brass screws attached to a brass ring. Draw a line
along the entire assembly, this is so you know where you started from. Once you loosen those
screws you can spin the assembly to close the flaps, then tighten but not too much, you don't
want to flatten that brass washer thingy. Then start it up and as its warming up make sure the
flaps slowly return to vertical. Thats how I did mine. Keep in mind though if you have to pump the
gas a lot its possible the fuel is draining backwards in the line and you just have to pump it back
to the carb for it to start.
[Its the other way around. Flaps should be closed when cold and open when hot.
On my first Weber I had a problem that the flaps would lock shut and I'd have to poke them with a
screwdriver to unlock them before starting.
EDIT: it is possible if the choke is working that you have an air leak in the intake system
somewhere - this will lead to hard starting]
Agreed but when you turn off the jeep when hot, the flaps are vertical and on mine at least they
stay that way even when it cools down, till you hit the gas and the engine is cold, then they snap
shut. On mine the pressure from the throttle linkage keeps them open till its released.
(Alright lets look at this. There are three main settings to be concerned with aside from a run only
hot link to the bi metal spring.
First would be the amount of tension on that spring to begin to close the plate to within 1/4" of
the air horn wall as the engine cools. This is accomplished as mentioned above in a prior post,
repeating that, loosen the cup retaining screws just enough to allow you to rotate the cup. Not so
much that friction is lost and the spring will cause the cup to rotate back. Go ahead a turn each
way and you will discover how much revolution is required to adjust the position of the plates.
Now rotate it until it is expected to stop, that being the gap I mentioned earlier. If it isn't no worry
it will when all three steps are performed. So for now rotate the cup until it closed against an
internal (unseen)stop and then rotate it say 1/8" more. This will preset a near enough to correct
setting for now.
Make certain there is enough tension of the retaining ring on the cup to prevent its rotation except
by the force of your hand.
Now locate the fast idle lever. It is behind that cup between it and the carb body. It will have a
linkage rod attached and that rod will extend into the lever attached to the choke plate. Look
closer at the lever and you will notice an adjuster screw kinda hidden behind the choke assembly.
It will rest on the fast idle step of that lever when set. If the lever will pivot without that screws
contact run the screw in until it just happens to sit on that step with the choke plate closed. Now
run it in say a 1/16th turn more. You will adjust the screw to suit your needs after the start up and
should be the only thing to adjust once these procedures are completed.
Next look at the far end of the assembly and locate the choke qualifier. IIRC turning it in will
richen the setting and out will weaken the mix. This is accomplished by how far away or near the
plate stops from the air horn as was mentioned earlier. This qualifier is powered by internal
vacuum channel. So if this last adjustment is done with the engine started vacuum will open the
choke to the 1/4" open if that adjuster screw is set correctly. If it needs to open more to be set
correctly, back that screw out. If it needs to be set nearer run it in.
If you want to set it with the engine off then apply finger pressure to the lower edge of the plate
to simulate the air flow. Adjust that screw in the same manner.
Now lastly on a fully cooled engine check this setting by opening the throttle plate at least half
way and see if the plates snap fully closed. If it does not rotate the cup until it does, tighten the
retaining screws and you got r done.)
I've haven't done this adjustment but it may help with your problem. I find that my weber acts up and won't allow starting when the throttle valve (the flap plates) are stuck in the closed position. usually, it will turn over fine and I know that the fuel pump is working. You may want to check this if you have starting problems.
Maybe JohnnyC and other weber gurus will chime in.
Best, ty
