I couldn't get it to start again this morning. Yesterday evening after running it out of gas I could only get it to start using starter fluid. Today I tried it and it won't start. It won't start if I give it a couple pumps and try, and it won't start if I hold the throttle wide open. I have not tried starting fluid today.
Here is the carb from the passenger side after several attempts to start it this morning.
Well, it's a just a mechanical device that'll do what it does without thinkin', so back to basic steps, is it getting spark, is it getting fuel.
Starts on starter fluid, so you're getting spark.
Next up, is it getting fuel, so, is it a mechanical or electric fuel pump?
If electric, pull the feed hose, stick it in a jar, and see how well it fills with fuel. If mechanical, pull it and manually actuate.
If it fills with fuel, check the feed to the float. I had mine rattle loose and stick the float closed.
Let us know!
Mechanical.
Did you watch the Carburetor Choke Operation video on You Tube that I suggested. It is a 4 bbl carb but the starting procedure is the same. GM produced the educational video to instruct new car buyers on the correct starting procedure. The same procedure for you to use. Watch the entire video. Thanks
In this picture of your carb, the red circle is the dashpot, also can be called a choke unloader. Where does the vacuum hose from the dashpot go to? Hopefully it goes to intake manifold vacuum which is any vacuum source below the throttle blade.
I also marked 3 red stars. Where does the one on the left go to? I am hoping it loops around to the PCV valve. The star in the middle looks like it goes from intake manifold vacuum to intake manifold vacuum. And the clear vinyl hose on the right does not belong on a car and should be replaced, but for now, where does it go?
Intake manifold vacuum is any port below the throttle plates and is measured at idle
Ported vacuum is any port above the throttle plate and is measured off of idle
And back to the dashpot. The dashpot's job is to use intake manifold vacuum to pull the choke open a measured amount when the engine attempts to start. This is to keep the engine from flooding from a fully closed choke. To test the dashpot you need a vacuum source, and that can be you! Disconnect the hose (gently) from the dashpot itself and stick a section of clean hose that fits snuggly on the dashpot. With the engine cold and the choke completely closed suck on the hose you put on the dashpot.(Yuk) You should see the linkage move and pull the choke open a tiny amount.
Something else I just thought of. Do you have a test light?
It is a handy tool to have when working on vehicles. A volt meter works, but sometimes a test light is just easier.
The reason I ask is you need to check for voltage at the wire that goes to the choke. With the key in the run position the wire to the choke should have a nice bright light or battery voltage.
You might also replace those little vacuum hoses. As the rubber ages and gets hard, they lose a little effectives for their intended purpose.
Don't know if anyone has mentioned this yet so . . .
The pic (cropped by me) is your choke activator. It is activated via the attached wire.
There are 3 screws on the face. They can be loosened so you can adjust the choke so it is fully open when the engine is at operating temp. Loosen the screws and turn the black face to adjust the choke position.
Do not forget to tighten the screws when done.
In reply to ГУЛАГ мальчик УР следующий :
The fuel hose is a hard line from the pump to the carb. You want me to unscrew that and test if for fuel?
In reply to outasite :
When I plugged "GM carb operation video" in YouTube I got tons of hits and didn't know which one you were talking about.
In reply to Noddaz :
Stars 1 and 2 join each other and go into the intake. The clear hose is on me, the rubber hose was missing when I got it and I didn't have any fuel hose at the hose so I used the clear to plug it. I have been to the auto parts store 3 teams and forgot to get a rubber hose.
I haven't tested the dash pot yet
In reply to Noddaz :
I do have a test light and I will test it.
octavious said:In reply to ГУЛАГ мальчик УР следующий :
The fuel hose is a hard line from the pump to the carb. You want me to unscrew that and test if for fuel?
Yep, need to make sure fuel is getting to the carb.
Fuel pump looks new, recently replaced?
If no fuel getting to carb, then make sure there's no obstruction in the lines.
To test the fuel pump, run a line to a small container of fuel on the intake end of the pump, see if it spits gas on the outlet end.
If that's all working, it should run.
In reply to Noddaz :
Test light shows power at the choke with the key in on position.
In reply to ГУЛАГ мальчик УР следующий :
I don't know the age of the fuel pump. But...are you saying not to use the line from the tank, but add a new container of fuel? Or is the line from the tank fine but to pull the outlet from the pump and test it?
octavious said:In reply to ГУЛАГ мальчик УР следующий :
I don't know the age of the fuel pump. But...are you saying not to use the line from the tank, but add a new container of fuel? Or is the line from the tank fine but to pull the outlet from the pump and test it?
Disconnecting from the tank line and pulling fuel from a jar will isolate the test to just the fuel pump.
So, easy button, pull line off carb, test.
Then, if you're getting robust fuel in to a container, then everything from the tank forward is ok, and you concentrate on the carb itself. Caveat: it won't tell you fuel PRESSURE, though - most carbs need a certain amount of fuel pressure to run right. More at the end.
If the flow is a dribble, or nonexistent, then move back to the pump, pull tank line off, run a hose from a can of fuel in to the pump so it's pulling from an easy source.
If the pump spits fuel at a good rate, the pump is probably ok, and you have a restriction from the tank.
If the pump doesn't pull from the jar, then you know you need a pump.
Caveat explained a bit more; if everything seems ok, and it moves fuel no matter what you throw at it, then even though it seems ok, the pump might not be generating enough fuel pressure, might still need to be replaced.
So, get a little fuel pressure gauge your next run to the parts store. I've got one sitting between the fuel feed and the carb, so whenever I crack the hood with the motor running I can take a quick peek.
Anyway, you just keep moving back towards your fuel source until you find an issue.
I've followed all of these steps when I was getting mine running, and it's a simple process. Once I fixed my loose float valve issue, the car stalled again, so I pulled the cover and it was still tight. What the...?
Moved back to my electric fuel pump, fuel was a dribble. Replaced pump, car been running great the last couple years.
octavious said:In reply to Noddaz :
Test light shows power at the choke with the key in on position.
This is good! The voltage warms up the spring and helps open the choke sooner to be more efficient.
Is the dashpot hooked to intake manifold vacuum?
And to take the line off of the carb you need two wrenches. One for the big carb nut, usually 1 inch if I remember correctly and a flare nut wrench to keep from rounding off the nut on the fuel line. Same thing at the fuel pump. One wrench on the block on the fuel pump and a flare nut wrench on the fuel line. And do you have a vacuum pressure gauge?
You can test the fuel pump with it. With the line disconnected at the carb you plug the fat adapter to the gauge and wiggle the fat adapter onto the fuel line. Crank the engine over a few times to see if you have fuel pressure*. If you do then you can go to step B. Hook the carb back up and pull the fuel hose off the inlet to the pump. Plug the fuel line with a bolt or something to prevent fuel leakage. Plug the fat adapter to the inlet of the fuel pump and repeat the test. The gauge should show some level of vacuum pulled and the pump should be able hold that vacuum. If the fuel pump makes pressure and holds vacuum, the pump is good.
*I do not remember the exact spec here, but I will look it up.
In reply to octavious :
Title of video is:
Carburetor Choke Operation
Type this into search exactly as written
It is the 2nd video, black and white, produced by General Motors Rochester Carburetor Division.
Please watch it. It will assist you
In reply to outasite :
https://youtu.be/_BTEdWt2V3s?si=XpVRSpbp3LuYFlnj
This is the one I just watched, I hope it is the correct one. I get how it is supposed to work. And I have another question. In the video the proper procedure is one press to close the choke fully. The Jeep has Sat sent yesterday morning, but when I press my gas pedal once my choke doesn't close. In fact it looks like the last picture of the carb that I posted. Which in my mind means I need to see the choke closed on a cold engine. Correct?
And do I adjust the choke to be closed using the choke actuator as L5wolvesf posted? Or is the actuator only for adjusting it to fully open? I guess I need to know how to close the choke because this diagram makes it sound like I bend the rod to adjust.
In reply to Noddaz :
Following back up with you. According to this diagram, it looks like I have a Thermostatic lockout valve.
Hard to see but this is on my engine, with the bluish cap. Is the port where I have the clear hose supposed to attach to this valve? But where is the bottom hose supposed to go?
In reply to Noddaz :
Vacuum on the dash pot causes the lever to move, but it doesn't move far enough to move the choke.
I adjusted the choke to close by adjusting the choke as L5wolvesf said. It wouldn't start. I hit it with starting fluid and it started fine. I tried again 5 mins, 10 mins and an hour later and it restarted first crank.
I'm going to let it sit until tomorrow morning and then try it again.
In the AM the choke plate should be fully closed after you give the accel pedal one pump.
Then it may need a 2nd pump to fire up.
Then when it is up to op temp the choke plate should be fully open.
Todays report... one pump did not close the choke all the way, so I tried two. It didn't close either, but it started on the first crank. I drove it around for 30 mins and stopped to top off the tank with ethanol free. After filling up it started again on the first crank and I just got home. It seems to be working better. I won't say perfect, but definitely better.
octavious said:In reply to Noddaz :
Vacuum on the dash pot causes the lever to move, but it doesn't move far enough to move the choke.
It should only move the choke from the fully closed position to slightly open when the engine starts. If the choke does not fully close, the dashpot can't pull it open.
And now you also know it takes two pumps to start your Jeep.
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