Choke adjustments and Cheap Chinese carburetor WARNING

rcarlisle wrote

What part of SC?  WE have crews working down there this month at severalplaces, Ladson, Marion, Lexington, N Charleston last month, Beaufort last month.  

I'm all the way up I-77 at the VA line, but not far off I 74 where it splits and goes South separately.  Mt Airy

Mt Airy?  As in "Mayberry?"  Say hello to Andy for me.  

I am in Florence, SC.

rcarlisle wrote

 Before I got started on this again recently, the truck would be warm (gauge and heat) but the choke would not come down to hot idle.  So that's been my thing.   Getting the choke system working from scratch.  

It could be something as simple as a faulty choke cap.  You can try the chinese choke cap and see if you get the same results.  But I still think you need an electric assist choke cap to make the choke work more accurately.

 

Yes as in "mayberry" - ugh.    Goober says HEY

The sales person I support is in Summerton - apparetnly when they go to "town", they go to Florence.   We did a Gulf station in Marion last week.  Had to go to the Sherwin Williams in Florence for paint.  HAve done other stores in the past in Florence as well.   If there was ever a Kangaroo store, you've seen my work.   All in the past as they are owned by Circle K now.

The cap on the Autolite is the one that was on it when I bought it.   I'm using the Autolite again since losing the screw.   I put a hair dryer to the spring in the cap and it moves quickly when heat applied.   I did consider putting the Chinese one wire cap on the Autolite, but would really not like to have to do that wire deal to the Alternator - no easy way to get my fat hiney down to the alternator.   Pretty sure it was me turning the screw in teh white plastic thing in the wrong direction.   Hope to get that adjusted this evening.

Can't find a screw that will thread back into the throttle shaft of the Chinese unit.  

LARIAT 85 wrote

First - shame on you for buying a chinese carburetor.

Second - you are supposed to set the high idle speed to 1600 RPM when the engine is HOT, like I said in one of your earlier posts.  You do not want your engine to shoot up to 1600 RPM when it's started in the cold.

Third - if it is really cold, your choke should *not* come completely off - if at all - when you hit the gas too soon.  As the engine builds up some heat and the choke spring relaxes a little, hitting the gas should bring it down to the next step of the carburetor, which should drop the idle speed down to about 1000 RPM.  When your engine is at full operating temperature, your choke plate should be completely vertical with tension holding it open and your engine should be idling at curb idle speed.

Fourth - Provided it is set up correctly, a thermostatic choke will always work better than an all-electric choke.

Ford used supplementary heat to help the thermostatic choke open up completely and faster, and to stay open when the choke isn't really needed.  In the 1960s, a heater hose was routed against the choke cap.  In the 1970s and 1980s, an electric assist choke cap was used.  You are using neither, and that is probably why your choke isn't opening up all the way.  The only way to get it your choke plate completely vertical without the heater hose or electric assist choke cap in place is to make the choke really lean (very little tension), but then that means the choke isn't going to stay on long enough.

Replace your choke cap with an electric assist choke cap and hook that to the alternator and I bet your problem will go away.

Here is one I found for you:
https://www.ebay.com/itm/371957582173?epid=174779043&hash=item569a66495d:g:7YIAAOSwY3BZIb3i

Ok, yesterday, I checked the vac pulloff.  Document on here for a 1980 said right around 1/8" measured at front of choke plate.  Did that.   THen set the choke arm to the first step off high idle.   Checked and adjusted the choke arm adjuster.   Drove to get gas (~4 miles).   Seemed to be stumbly right out of driveway, but got better by the stop sign 1/4 mile away.  I had to tighten up the pulloff to get 1/8" and there is play in the plate.  It ran better first thing a little more open (the old setting by eye).  I may open that vac pull off a little more.  1/8" at front is not much opening of the choke plate.

At the gas station, I had to adjust on the choke arm adjuster to get the plate to drop to fully open.  

I also put the choke arm on high idle and the rpm is at 1600 hot.  

I'm not sure what the hot idle should be for a manual trans.  600 sounds good, but is that too low for proper lubrication?  The sticker on core support is for an auto trans.   It says 875 in Neutral?  I need to take a pic of that for reference when away from truck.  

This evening's cold start will be with no checks or adjustments.   Just a cold start and see if it works properly.  

I think 550 - 600 RPM hot is a good idle speed.  There's nothing magical about it, and there should be plenty of oil flowing at any speed for good lubrication  After all, the engine is just ticking over and not pulling a load.

On the choke pull off measurement, or any of the other adjustments, my thinking is that the factory specs are a good starting point.  But I usually adjust things a bit more after setting up a carb to the factory specs, and then when I rebuild the carb I don't change anything.  Each carb and each application are slightly different and once you get it "right" then there's no need to change it back.

Thanks.   I agree that on a 40 year old truck, factory settings are a starting point.  I tried the smaller opening, but it was working well before the adjustment and I think I'll go back.   But I am trying everything to make it best possible.  And getting closer and closer.  

As for idle speed, I ask because.... Harley guys want that slow  slow slow idle.   And that kinda works on a harley.   But the other cruiser brands want that slow idle, but the oiling system doesn't work under like 600 or something.   Just didn't want to hurt the engine with too low Idle speed.  But any hot idle under 1200 is making me happier these days.  

I *think* the previous tuners of this engine had the fuel just opened up on hot idle til it would start and run with no choke.  LOTS of idle screw fuel.   So now we're getting it refined.  Come warmer weather, going to remove plugs and probably replace or at least clean them really well if they look ok.   Engine doesn't have that many miles since install, so they may be okay, but all the carb adjustments may have them feeling a bit rich?  

This year won't be so much replace and fix up so much as getting what I have refined and working properly and better.  

I am not sure I understand what you mean by the 1/8" measurement on the choke plate.  Is that the gap when you first set the choke?  If so, that may be your problem.  On my Autolite 4100, my choke plate snaps completely shut (less tension when temperatures are warm, more tension when temperatures are cold) when I first set the choke/prime the carburetor for the first cold start.  Then when the engine fires up, the choke plate immediately cracks open about 1/8" and gradually opens up from there until the choke comes completely off.

For example:

I drove my truck last week when it got down to the 30s.  It was the first drive of the day, and I had driven it the day before.  I get in, and step on the gas pedal once to set the choke and get a shot of gas down the intake.  Because of the cold weather, I can actually hear my choke plate snap shut. It has a bit of tension holding it tightly closed against the air horn. The throttle is now set on the highest step of the fast idle cam. I key the engine, and it quickly fires up and starts [fast] idling at about 1250 RPM.  The choke plate cracks open about 1/8" as soon as the engine fires up.  

Since it is so cold outside, the spring in the choke cap is tightly wound up.  So if I were to stab the gas pedal before enough heat has been generated from the engine, the fast idle cam would not drop down and the idle speed would not reduce.  But that's not a problem.  If I wanted to drive away right then, the load of the automatic transmission would drop the [fast] engine idle speed down to about 1000 RPM, which is enough to keep it running smoothly.  

But since I care so much for Lucille and I wasn't in any particular hurry, I let the engine idle for about 30 seconds - just like I do with my fuel injected vehicles when it's that cold.  As the engine begins to build up some heat, the RPMs will slowly start increasing.  When it gets up to about 1600 RPM (hot fast idle setting), I give the throttle a quick but gentle stab. By this point, the spring in the choke cap has relaxed enough to drop the fast idle cam down to the second step. In turn, this drops the [fast] engine idle speed down to 1000 RPM.  But that's not a problem.  If I wanted to drive away right then, the load of the automatic transmission would drop the [fast] engine idle speed down to about 750 RPM, which is enough to keep it running smoothly.  

This is a good time to drive away and let the automatic choke open up the rest of the way gradually.  Again, your engine will get up to full operating temperature faster in 2 miles of [conservative] driving than it would if you let it sit and idle for 15 minutes.  And that is actually better for your engine than letting it sit there and idle.

If I choose to sit there a bit longer, the engine speed will begin to rise again.  When it gets up to about 1600 RPM (hot fast idle setting), I give the the throttle a quick but gentle stab again.  By this point, the spring in the choke cap has relaxed even more to drop the fast idle cam completely off the throttle. In turn, this drops the engine idle speed down to 750 RPM, which is my curb idle speed in PARK.  If I wanted to drive away right then, the load of the automatic transmission would drop the engine idle speed down to about 500 RPM, which is enough to keep it running smoothly.  


Capiche?

You got it perfectly.   That is what I would like to get tom if I can get it all adjusted correctly.  

The 1/8" measurement is exactly what you said.   We're on the same page.  

Ok, Lariat, Help me out here.  Or anyone.  

Drive truck last night - no adjustments whatever.   Choke did all it was supposed to do EXCEPT that last step to hot idle.   The choke plates were still partially closed and the high idle was on the last step of high idle cam.   I went to check it, touched the linkage on choke side lightly, and it dropped to hot idle and choke vertical.   So I need just a touch more heat in there?  

Do you guys think I could put that metal plate in front of the choke housing?  To reduce cool air from front of engine.  The choke housing might read hot enough to let it open fully.  I'm also considering trying to get the hot air tube in contact with the exhaust manifold to put more heat into the tube going to carb.  If I can bend it over to be in contact, might be able to run a hose clamp around it all.  

I don't want to loosen the choke cap any more at this time of year.   Not sure if there is anything else short of electric assist choke or full electric.   And I need less than 12v switched for an electric assist cap, right?  Not full 12v?

I feel like I'm dangerously close to having it working right.  

My first thought was to back off the choke cap one notch.  I think that will open it up fully and drop the fast idle.  And if it doesn't you can put it back where it was.

As for the electric assist, it does use the 7v off the alternator.  And the 1981 factory shop manual says:

The hot air choke with the electric assist choke cap functions as follows: as the engine warms up, manifold heat transmitted by hot air to the choke housing relaxes the bimetal permitting the choke to open. The electric assist has a ceramic heating pill. At temperatures above 12 degrees C (54 degrees F) to 23 degrees C (74 degrees F), the temperature sensing switch closes and current is supplied to the heater causing the bimetal to pull the choke plate open at an increased rate. The electric assist choke cap is powered from the stator tap of the alternator.

I tried it, Gary.  And it worked!   Took a little longer than I thought, but that may be me.  But it worked.  

Unfortunately, it's raining and on my test drive at turn around point, truck started missing badly.  I pulled under a leaky carpet at a church, found nothing amiss.  Figured I'd limp home.  It cleared up and ran fine by the time I got home.

So I'll be waiting till it stops raining before I try it again.  And my heat seems to be sick in defrost position.  Dang it.  Frustrating.

But your tip seems to have worked for the moment.  Thanks

rcarlisle wrote

 Do you guys think I could put that metal plate in front of the choke housing?  To reduce cool air from front of engine.  The choke housing might read hot enough to let it open fully.  

Yes.  That is why Ford put that plate there.  So put it back!

rcarlisle wrote

I'm also considering trying to get the hot air tube in contact with the exhaust manifold to put more heat into the tube going to carb.  If I can bend it over to be in contact, might be able to run a hose clamp around it all.  

I just thought of something:
When I first put together my choke stove, I sandwiched a section of aluminum tubing inside of the choke stove dome with the choke stove mesh filter inside of it, and that assembly was clamped down on the exhaust header.  Then I pushed the two choke tubes into either end of the dome, which went into that slighter larger tube with the filter media.  I seem to remember I had the same problem you are having.  

So I replaced that section of aluminum tubing inside the choke stove dome with a piece of copper tubing.  And that mostly solved the problem.  Now it got hot enough to open the choke completely, but the choke plate was somewhat loose.

What made it work perfectly is when I connected the electric assist choke cap to the back of the alternator.  Now when the engine is up to full operating temperature, the choke plate is completely vertical and held open tightly.  


Another advantage of the electric assist is that I never have to make seasonal adjustments to the choke.  

Good!  I'm glad it worked.  

LARIAT 85 wrote

rcarlisle wrote

 Do you guys think I could put that metal plate in front of the choke housing?  To reduce cool air from front of engine.  The choke housing might read hot enough to let it open fully.  

Yes.  That is why Ford put that plate there.  So put it back!

It wasn't on there when I got the truck.   So I scavenged the one off the cheap Chinese Carb.   And the screw even worked!  Guess I'll just let that one sit and use it for learning purposes and whatevr parts might can be used.  lol  May try the electric assist cap off of it to see if it helps make sure we're getting the choke opened fully all the time.  

I need to find my spacer I had to have for the chinese carb or trim the plate so air cleaner housing will fit down.  

Thanks for all the help.  Hopefully if someone else sometime is having issues, they can learn from my experiences.   I did read a LOT of posts on here and FTE, plus YT vids to get to this point.  

This year looks to be a year of figuring out all the things that the PO and garage that did engine install did that could have been done better.   Refining and improving the old truck instead of letting it slide into a worse case of disrepair.   The PO sold it because he couldn't afford to continue his "restoration" because Covid had him out of funds.  

There are always things to do to these trucks to make them better.  Frequently it is better than the PO, or his ham-handed mechanics, made it.  And after that you can make it better than stock.  But there's always "better" to be had.  

That's the spirit!    

You cannot expect these old carbureted vehicles to run as good as newer fuel-injected vehicles when parts are missing or mismatched. But that is just what many people do.  (I don't mean you.)  Previous owners and incompetent mechanics will often leave off vital engine parts over the years and are dismissed as "smog junk" or "not needed" without really understanding what they do.  Just like any modern vehicle with EFI, ALL of the parts need to be there and functioning properly for a carburetor to function as designed.  

I have been there.  Lucille originally had a feedback carburetor system.  When I got her, all of the emissions equipment was long gone.  Vacuum hoses were plugged with screws all around the truck.  The carburetor was replaced with an older one without the feedback solenoid, so the confused engine computer was always in "limp home" mode.  The AOD wouldn't shift right because the carburetor had the wrong linkage on it.  The entire choke system was missing, so I had to nurse it when the engine was cold.  And it had an open-element air cleaner on it, just like a race car.  But it ran like that for years and sounded cool with the low idle and dual exhaust.  I didn't know any better, so I dealt with it and thought that was normal for these old carbureted vehicles.

Modern EFI vehicles have an engine computer that can self-tune and trip the CHECK ENGINE LIGHT to tell you if something is not right.  These older vehicles can't do that, so you may not realize there is a problem.  Then the conclusion is that this is typical behavior for an old vehicle with a carburetor, just like I did.  Except it is not.  A carbureted vehicle *can* run as well as any modern fuel injection vehicle.  Even in very cold weather.  But is has to be tuned correctly and with ALL of the required parts!  

Randy,not a 302 but a 300 six running EFI manifolds so I had no way to get hot air to the hot air asst. choke assy.

I bought copper tubing that would fit the choke housing and wrapped it around the manifold a few times, think 3 loops. It is hooked to the carb just like the factory did other than the loops.
The first few times I drove the truck to work when the temp was 28* or lower the fast idle would not come off.  

I first leaned out the choke by adjusting the housing but did not really help.
Then I was thinking I needed more loops to get more heat in the air. I made sure the loops were as tight to the manifold as I could get them, still not pulling the choke open off fast idle and to add more loops was going to be a PITA!

What worked was header wrap. I think I used about 6 feet in my case and wrapped the loops & manifold to keep the heat in place. That seamed to work as the fast idle dose come off a lot sooner.
I think I seen your post the "loops" are around the head pipe? If so I wonder if the "heat" is getting blown away and not heating the tubing?

Also in your case the hot side of that tube is also out in the open running up to the choke housing.
My hot side is between the block and manifolds, remember its a 300 six.
Could any of that hot air also being cooled being out in the open going to the carb?
Maybe header wrap around the head pipe / tubing and around the tube going to the carb would keep it hot enough to get the choke to open all the way?

The other thing that has me thinking of your set up / testing / checking is are you driving with the air filter housing off? If so more cold air could be blowing across the carb / choke housing and cooling it.
The air filter kind of traps heat and keep cold air from blowing across it.

So far in my case the choke is working as it should after the header wrap.
I can drive the truck right away if I want. Mine is parked in the garage but I start it up back it out, run back in to make sure dogs are in the bedroom with the wife and gates closed so they cant got to the kitchen and lights off before driving. If at work it is like you, settle in belt on and drive no issues.

Just some things that worked for me that may help you or others.
Dave ----

ps I dont know if the choke is open 100% but the AFR meter is not rich like it was before the header wrap.

For a number of years Ford carburetors had a clamp built into the shield on the choke side that held the heater supply hose against the choke cap. This served two purposes, in cold weather it delayed the choke opening by keeping cold coolant against the cap and once the engine was warm in any weather it helped keep it open, or to reopen quickly by having warm or even hot coolant against the cap.

85lebaront2 wrote

For a number of years Ford carburetors had a clamp built into the shield on the choke side that held the heater supply hose against the choke cap. This served two purposes, in cold weather it delayed the choke opening by keeping cold coolant against the cap and once the engine was warm in any weather it helped keep it open, or to reopen quickly by having warm or even hot coolant against the cap.

 
I have seen that mentioned a couple places, but havean't seen any photos of it - that would be a thought, but I think we are getting closer.  

FuzzFace2 wrote

Randy,not a 302 but a 300 six running EFI manifolds so I had no way to get hot air to the hot air asst. choke assy.

I bought copper tubing that would fit the choke housing and wrapped it around the manifold a few times, think 3 loops. It is hooked to the carb just like the factory did other than the loops.
The first few times I drove the truck to work when the temp was 28* or lower the fast idle would not come off.  

I first leaned out the choke by adjusting the housing but did not really help.
Then I was thinking I needed more loops to get more heat in the air. I made sure the loops were as tight to the manifold as I could get them, still not pulling the choke open off fast idle and to add more loops was going to be a PITA!

What worked was header wrap. I think I used about 6 feet in my case and wrapped the loops & manifold to keep the heat in place. That seamed to work as the fast idle dose come off a lot sooner.
I think I seen your post the "loops" are around the head pipe? If so I wonder if the "heat" is getting blown away and not heating the tubing?

Also in your case the hot side of that tube is also out in the open running up to the choke housing.
My hot side is between the block and manifolds, remember its a 300 six.
Could any of that hot air also being cooled being out in the open going to the carb?
Maybe header wrap around the head pipe / tubing and around the tube going to the carb would keep it hot enough to get the choke to open all the way?

The other thing that has me thinking of your set up / testing / checking is are you driving with the air filter housing off? If so more cold air could be blowing across the carb / choke housing and cooling it.
The air filter kind of traps heat and keep cold air from blowing across it.

So far in my case the choke is working as it should after the header wrap.
I can drive the truck right away if I want. Mine is parked in the garage but I start it up back it out, run back in to make sure dogs are in the bedroom with the wife and gates closed so they cant got to the kitchen and lights off before driving. If at work it is like you, settle in belt on and drive no issues.

Just some things that worked for me that may help you or others.
Dave ----

ps I dont know if the choke is open 100% but the AFR meter is not rich like it was before the header wrap.

I have studied your setup in other posts and considered doing that.  BUT I am afraid to try to remove the manifold for fear of breaking studs.  IF I were to get the manifold off, I could actually try to fix the OEM passage.  

I have thought on different stuff too.  I may try to slide that heat shield UP to hold in the heat that starts on the down pipe.  It gets warm, but not too hot to touch.  That's I've seen yet.   Some ding dong in the past has the dipstick tube hoseclamped to the drivers side manifold and I can say without hesitation that it gets HOT to the top.  That's why I think I might try to move that tube over and clamp it to the manifold.  OR move the Dorman things up to the side of exh manifold.  Just possibilities.

Adding that shield in front of choke linkage seems to have helped as well.  

I've done some with the air cleaner housing off, but have got it to a point where I'm starting and driving with the housing on.   I have it working pretty well.   Wish I had understood the choke arm adjuster before I put the carb on.   Can't see the V on the high idle cam with it low and behind the choke housing.  Having to work by feel.  All this would have been easier a few years ago.  For several reasons.

So, I can almost drive off immediately.  It takes a few seconds to catch and run good.  It sits and stumbles a little unless I give it about 3 presses on the gas.  Not enough fuel from the accelerator pump?  Idk.   It seems to be adjusted to the proper hole.  But there is a gap between the arm and the post.   That might bear investigation after I get the choke working as a whole.  But usually, once it catches properly, it's ready to go by the time I get settled with belt on and my "stuff" secured in the console.   Coffee or drink, phone, my "huffers" (I vape).  

I'll be glad to get all this done so I can put all the screwdrivers and tools up that are floating in cab and console.  the closer I get it to working correctly, the more tools it takes?  It's frustrating, rewarding, and educational all at hte same time.  I'll be a local carb expert by the time I get it all figured out.  

I posted it for you and others if they come across this on a search for "choke".

Is there a way to run copper tubing around the manifold? I dont know if there is room between the manifold & block? A thought you dont need to make loops around the manifold you could make long loops along the out side front to back a few times. Maybe you can slip mechanical wire between block & manifold to hold the tubing close to the manifold.

Anything to get more heat to the tubing, like the header wrap I used.
It does take time to "dial in" carb adjustments like you and timing curves that I am on now.
Dave ----