Cold Start, Manual Choke CJ7 304 AMC

[CJ7NUB]

Hello,

I have a CJ7 with a AMC 304 AMC with a manual choke.



Just recently my 95 Ford Probe died, thus making this my current "driving" vehicle and it's a bit cold in Michigan. I purchase the engine, body, almost everything for the CJ7 and assisted in building this vehicle with my father around 16 years ago. I know just the bare minimum of how to drive a vehicle, and I take my vehicles to a mechanic for everything.



My questions are all related to getting the vehicle started (especially in the cold), the choke, the accelerator, etc..


Am I starting the CJ correctly:


My current method is; Pump the accelerator about twice & pull the choke all the way out, turn the key. Next I try to keep the accelerator down a little while I put the choke in the half position. I wait till I hear it idling on it's own with the "thing" at "half choke". I wait 10-15 minutes, push the choke in all the way and then try to drive it.



Questions:

1. How long should I keep it idle for before I try to drive it?
   1. What are a few signs that I have attempted to drive it too soon?
   2. what if the temperature never jumps above 180?\

1. Am I working the choke correctly, or/and is there a better method to ensure I can get the engine to idle appropriately?

1. What if the vehicle won't go above 15MPH after sitting IDLE with the choke open correctly/pushed all the way in. The vehicle just makes a puttering sounds, and a little backfiring sound. What can I do to fix this.

Nothing looked like it wasn't attached like a vacuum hose.

Did I just try to drive the vehicle too soon?


I'll probably have more questions later on & thank you.

 

[jp360cj]

Does it drive fine once up to operating temperature? Is this a new issue, an old issue, or have you not driven it often enough in the past to know?

When it sputters/backfires with the choke open, Have you tried to push the choke in some? Sometimes with mine if it's not fully warmed up I'll run the choke 1/4 to 1/2 way for a few minutes while driving.

 

[mriplaybass]

Sounds like you're doing things correctly, but, manual chokes can be a trick to operate correctly. If you push them in too soon, the engine sputters and dies. If you wait too long, you blow a lot of unburned fuel out the exhaust.
An automatic choke takes care of this for you, including a faster idle when cold. If the stove pipe for the OEM automatic choke is missing, you can always go with an electric choke. Easy to install, and it takes the guess work out of warm ups. Or you could just install EFI to the tune of $800 and up! (Just kidding )

A bit more information would be helpful. As JP360 asked, do you have these problems when warm.
If you still get stalling and backfiring once the engine is completely warmed up when you accelerate, it could be that your accelerator pump is bad, or the timing is way off.

It's not unusual for the temp gauge to run at 180° on a cool day. My temp gauge is digital in 1° increments, and in cooler weather, it runs 175° to 180°.

 

[CJ7NUB]

I appreciate the both of you responding.



I do not remember this issue in the past, but then again it has been 16 years since it was my main driving car. I didn't actually "drive" it this summer, it was only started up and ran around a lot but it didn't putter.

I was able to drive it last Sunday without a problem, (besides it being cold, and the defroster hardly working) I don't think that's anything new.



I would think 180 would be fine "driving" temperature, so and I timed it this morning I waited 18 minutes, by then the temp finally went above 180. It doesn't take me but 1 maybe two attempts to start it & to keep it idling.







I pushed the choke all the way in, put it in reverse and it felt like it hadn't even switched to reverse. Pressed on the gas peddle, nothing, I had to put it back into drive then back into reverse to get it to go in reverse.



I pulled out of my driveway, it of course sputtered around 15-20MPH so I pulled the choke out to around 1/3 back. Then it was "ok" I guess. I turned down a road to test if I could get it above 25. I was able to, it sputtered at first but then it was ok. I turned down a side road dropped the speed down to 20MPH... Sure enough it start to spudder (from the front of the vehicle), then it made a light "backfire" (came from the exhaust). I tried playing around with the choke, till i drove it back home... Nothing seemed to work.


It last had premium gas in it.



I wouldn't mind having an electric choke installed, but currently I'm content walking to work. Unless I'm doing something wrong it takes me less time to walk to work than it does to warm the thing up so I can drive it.

 

[shum8]

Am I starting the CJ correctly:


My current method is; Pump the accelerator about twice & pull the choke all the way out, turn the key. Next I try to keep the accelerator down a little while I put the choke in the half position. I wait till I hear it idling on it's own with the "thing" at "half choke". I wait 10-15 minutes, push the choke in all the way and then try to drive it.

First of all - Welcome to the forum....... I think you will enjoy your time here.

Now to your issue - I also have a CJ7 with a AMC 304 with a manual choke. They can be finicky sometimes at startup. The PO laughed and said his wife was notorious for draining the battery cause she never got the hang of starting with a manual choke.

Mine is quite cold natured - does not like winter. And for the record (shouldn't make much difference) I have an Edelbrock intake and carb..... My starting procedure is as follows: Press accelerator once to the floor, close choke all the way, push choke knob back open approx 1/4" and hit the key. As soon as it fires, open another 1/4" or so until I get a nice smooth fast idle. Give it thirty seconds, open till I get the slowest smooth idle and let it run for 5 minutes. Leave the driveway with choke slightly closed and after a couple minutes of driving, open the choke all the way.

That's my procedure, but every one may be a bit different. Good luck and keep us posted.

 

[Scout1067]

I have a AMC 258 i6 / 4.2l with manual choke and on cold days I have to start it with full choke and then push it in about halfway until the engine warms up before pushing the choke all the way in. If I push the choke in too fast it sputters.

It just takes some experience to figure out the right time to push the choke all the way in.

 

[mriplaybass]

Since you say that you timed it, it kind of sounds like it is starving for fuel once it is warmed up. If it's doing it all the time, and not just when you accelerate, it's probably not the accelerator pump. I would look at the fuel filter, the carburetor float adjustment, and possibly even the fuel pump itself.

 

[CJ7NUB]

"open till I get the slowest smooth idle and let it run for 5 minutes. Leave the driveway with choke slightly closed and after a couple minutes of driving, open the choke all the way."



I will have to try this, I'll definitely try this tomorrow.





"If it's doing it all the time, and not just when you accelerate, it's probably not the accelerator pump. I would look at the fuel filter, the carburetor float adjustment, and possibly even the fuel pump itself."


I appreciate the lead shortly after tomorrow when I try it out again, I'll have to look into these other possible area's to double check.



I appreciate all the advice again.

 

[CJ7NUB]

"open till I get the slowest smooth idle and let it run for 5 minutes. Leave the driveway with choke slightly closed and after a couple minutes of driving, open the choke all the way."



I will have to try this, I'll definitely try this tomorrow.





"If it's doing it all the time, and not just when you accelerate, it's probably not the accelerator pump. I would look at the fuel filter, the carburetor float adjustment, and possibly even the fuel pump itself."


I appreciate the lead shortly after tomorrow when I try it out again, I'll have to look into these other possible area's to double check.



I appreciate all the advice again.

 

[Manic Mechanic]

since you said you dont drive it much is there a chance you got moister in your gas or simply bad gas as the ethanol reeks havoc on old carbs and fuel systems

 

[Posi]

Sounds like you have something else going on.
You didn’t mention outside temps when starting.
180 on a cold day with a mechanical fan sounds right.
I had my Jeep out yesterday and never got above 174.
Outside temps were mid 20s (mechanical fan) and my 174 reading was correct.
I know this because I was checking my fuel BLM #’s and had my laptop connected to the ecm while I was driving, so no misreading gauge.
It’s also possible I have a 180 thermostat (haven’t checked) and you may as well

Starting a cold engine:
I don’t use the accelerator pedal on cold starts
Put Transmission in neutral
Pull choke out all the way (closed)
Turn key on
Push in the clutch to disengage the clutch, hold it in.
Crank engine
Once the engine starts adjust the choke until you get the proper idle speed.
Depending on the outside temps I sometimes leave the choke 1/4 out for about 1/2 mile of driving.

Starting a warm engine
Put Transmission in neutral
Turn key on
Push in clutch to disengage clutch
Press accelerator pedal half way down
Crank engine

 

[cglax6]

since you said you dont drive it much is there a chance you got moister in your gas or simply bad gas as the ethanol reeks havoc on old carbs and fuel systems

I agree...

Definitely a fuel delivery issue, but I don't think it's a 'procedure error' with how you operator your choke. You shouldn't have issues spitting, sputtering, and backfiring after you're that warm.

If you checked timing and it's good, I would start with getting the old fuel out and putting in new fuel...and replace the fuel filter.

If that doesn't help, then I'd pull the carb and take a look. If it's been sitting for so long, it may be gummed up and need a good cleaning. Check the floats...make sure they're set up correctly and move freely. Rebuild kits aren't terribly expensive, but rebuilding can be a little daunting if you don't know what you're doing...there are a lot of good youtube videos out there.

If you still run into trouble, the fuel pump may need replacing. It's not a complicated job, but can be a PITA when disconnecting fuel lines...fuel inevitable gets all over the place. Mechanical fuel pumps bolt in/out pretty easily.

While you're under the hood, it'll also be a good idea to pull and inspect your spark plugs. Make sure they're gapped correctly and clean (could be gummy or covered in carbon).

Also, check that air cleaner...if there's an air restriction, you won't run well either.

Let us know how it goes!

 

[Manic Mechanic]

If u do the pump and filter use a pair of vise grips and two pieces of a paint stick to crimp the hose on both ends this will greatly reduce the amount of gas spilled and less air to bleed out in the end. I use these but that's because I have them vise grips work just as well just takes a lil longer

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