All Small Six Choke Working Backwards

[FuzzyDriver]

My Autolite 1100 choke is set to 5/16" (per spec) when engine cold. Engine starts fine, but when you give it gas the choke CLOSES and the engine pretty much dies. Shouldn't the choke OPEN when you give it gas? If I floor it, the choke will open a little. What's the issue here?

 

[Frank]

My Autolite 1100 choke is set to 5/16" (per spec) when engine cold. Engine starts fine, but when you give it gas the choke CLOSES and the engine pretty much dies. Shouldn't the choke OPEN when you give it gas? If I floor it, the choke will open a little. What's the issue here?

Do you mean when the engine is running while cold the choke is open 5/16"? Or if engine is off you set it to 5/16" static?

Either way I'll give you the answer, just don't want to explain both.

 

[FuzzyDriver]

Frank, I set the choke to 5/16" open per the spec with the engine cold and not running. The choke doesn't move when I start it, so 5/16" either way. But now I have a worse problem. I got it started after cleaning/regapping the plugs, it runs terrible, ran the idle adjust up to keep it running, horrible clatter coming from rear. Figured it was cylinder #6, pulled that plug wire while engine running. Made no difference. Spark was OK (don't ask me how I know that *OUCH*). Black smoke pouring out the exhaust pipe. I guess it's got a stuck valve now to go along with the carb issue. I just can't seem to get this 200-6 to run well for long! Tomorrow I'll do a compression check on #6, but I don't see how it could be OK. Static compression checks I did when I first got the car were #1-#6: 150 160 170 166 160 156

Would a stuck needle valve cause this? Reason I ask is that, while adjusting the Idle Screw, I felt around under it where the throttle shaft enters the carburetor, and my finger got wet with gas. Just as some more info, I have an electric fuel pump and a Holley regulator set to 4 psi.

 

[Frank]

OK. . . Did you have the throttle opened up some when you set the choke? The choke will not close with the throttle closed, the high-idle cam blocks it. What it sounds like to me is, you have the choke coil too tight. the throttle must be propped open enough to clear the high-idle cam to set the choke-closed setting. From your first post, when you race the engine the choke is closing more. That would verify that you have the coil (way) too tight, from setting it with the throttle closed.
Before anything else: prop the throttle open about 25% total. Don't use WOT, that also moves the choke open. With the throttle propped open, now close the choke by rotating the coil until the choke blade is lightly touching the housing, that is, fully closed. At that setting, press on the blade with your finger, it should have very little resistance to opening. Lock it there and see if your issue is not solved. Forget about 5/16" or whatever for now.

 

[FuzzyDriver]

Frank, thanks so much for your post. Wish I could have tried your advice earlier this week, but I just got over my knee's steroid shots. These are not fun.

Before continuing, I cleaned and regapped all six plugs and spent an hour resetting the points to as near perfect as I can get them (points gap was on the high side). Following a different thread, I also checked my harmonic balancer by turning the engine over by hand until #1 was exact top - timing point was exactly at zero, so spun balancer is not my issue.

Following your directions, I propped the throttle about 25% and set the thermostat so it was just barely closed and easy to open. I guess I need to completely ignore the marking on the thermostat. Following your directions, the thermostat index ended up about 90º looser (i.e., it's pointing straight starboard now). I had the idle set way high to keep the engine running (due to my miss on cylinder #6). Car started immediately, ran very rough, and clattered loudly (just like it did before). I ran it at high RPM until it warmed up. Seems like it burnt away the stuff in #6 once it got hot because now the clatter stopped, it's running pretty smooth, and the idle went way up. Even though warmed up, it was still on the fast idle screw. How hot is it supposed to get before it drops off fast idle to the regular idle setting?

More importantly, do you think my OCD-ing the points gap and your procedure for thermostat setting actually fixed my super-rich condition that was fouling my plugs and killing my MPG?

After warmup I hooked up my old Sears 'Engine Analyzer'. Despite my careful points setting, it shows 25.5º at 680 RPM. Spec says dwell should be 35º to 38º at idle. There's no way I was that far off. Not sure I should trust the meter now or can something else be wrong to get a different dwell angle (when running) even when point gap is correct (with engine off)?

 

[Frank]

Frank, thanks so much for your post. Wish I could have tried your advice earlier this week, but I just got over my knee's steroid shots. These are not fun.

Before continuing, I cleaned and regapped all six plugs and spent an hour resetting the points to as near perfect as I can get them (points gap was on the high side). Following a different thread, I also checked my harmonic balancer by turning the engine over by hand until #1 was exact top - timing point was exactly at zero, so spun balancer is not my issue.

Following your directions, I propped the throttle about 25% and set the thermostat so it was just barely closed and easy to open. I guess I need to completely ignore the marking on the thermostat. Following your directions, the thermostat index ended up about 90º looser (i.e., it's pointing straight starboard now). I had the idle set way high to keep the engine running (due to my miss on cylinder #6). Car started immediately, ran very rough, and clattered loudly (just like it did before). I ran it at high RPM until it warmed up. Seems like it burnt away the stuff in #6 once it got hot because now the clatter stopped, it's running pretty smooth, and the idle went way up. Even though warmed up, it was still on the fast idle screw. How hot is it supposed to get before it drops off fast idle to the regular idle setting?

More importantly, do you think my OCD-ing the points gap and your procedure for thermostat setting actually fixed my super-rich condition that was fouling my plugs and killing my MPG?

After warmup I hooked up my old Sears 'Engine Analyzer'. Despite my careful points setting, it shows 25.5º at 680 RPM. Spec says dwell should be 35º to 38º at idle. There's no way I was that far off. Not sure I should trust the meter now or can something else be wrong to get a different dwell angle (when running) even when point gap is correct (with engine off)?

Glad something helped! First, about the choke:
It should open itself completely open in less than 5 minutes. If it's still idling high, the choke may not be unloading (opening) correctly. Verify that the choke blade is straight up after 5 minutes from cold start. If not, we'll cycle back to that. 2) Yes the setting I recommended cold will probably end up too lean once the rest of the choke operation is verified, and you're operating the car normally. And yes forget the mark on the coil cover, set it how your engine wants it. All my auto chokes are at least four or five notches on the lean side of center when they are set for best function @ max economy. Always err on the side of a lean choke, needs to be just adequate to effect getting started and out the driveway. Rich choke wastes gobs of gas, washes oil off cylinders, and other bad stuff.

Points: The smaller the point gap, the higher the dwell. Higher dwell = hotter spark, especially as rpm increases. Whatever points gap you set with the feeler gauge, take 4 thousands out of it and the dwell will be close. Like the choke readings, often setting points by the book feeler gauge setting will not be accurate on an old engine. Reason: As the rubbing block which opens the points wears over the decades, it takes less gap to equal the same dwell time. Correct dwell is the target, not the measured gap. I once had a very ragged Chevy6 work truck with 350K hard miles on it. The dwell was correct with a .010" point gap because the distributor rubbing post was so worn.
Remove points gap a few thou at the time until the dwell is in range. . . Less gap also advances the timing, but the change you need should not be enough to have to reset it.

 

[B RON CO]

Hi, when doing Ford tuneups many years ago, we would remove the plugs, and next, we would change the points and condenser. Before installing the new spark plugs, we would hook up the tach and dwell meter, and spin the engine with a remote starter switch. It is easy to adjust the points this way before the final screw tightening, and final dwell check. A good test for distributor shaft wear is to run the engine with the tach and dwell tester hooked up, and raise and lower the RPMs. The dwell should stay steady. If the dwell goes up and down, the cause is a worn distributor shaft or shaft bushings. Set the ignition timing before adjusting the carb, and now on our old engines, I always check the vacuum advance diaphragm. Good luck.

 

[DON]

Great info from both of you! I just had a thought, the fast idle doesn’t really come off by itself, the choke will, but fast idle needs a throttle blip( to half throttle- ish ) to allow it to return to normal idle speed. Same when cold to set the fast idle, a little throttle blob before starting. This may not need to be mentioned but it is a step that needs to happen

 

[FuzzyDriver]

Thanks all for your advice. There's really no way to adjust anything except Frank's advice to take .004 off the point gap until I get the intermittent misfire resolved. It ran OK for a while (as I said in my previous post) so I took it for a drive. Within a 1/2 mile it started surging and would not idle. I ran the idle up to keep it running (hitting on five cylinders). It was clattering terrible from the area of #6 again. After the major plug fouling business, I figure that it's a stuck valve for the same reason. It started running smooth again about half-way home and did 35 mph through town idling smoothly now that it's a six cylinder again. I bought two SeaFoams, one for the gas and one for the oil (oil takes 1 oz/quart). I'm hoping that the SeaFoam will clean up the stickiness and I can get back to tuning it. Do you guys have any experience with sticking valves and what you did to get rid of the issue? I'm trying SeaFoam because it seems to get rave reviews, for instance on YT Project Farm.

 

[FuzzyDriver]

Warmed it up. Choke wasn't all the way open so I turned it some more. It's now open all the way and the pointer is straight down :^/

Drove it twelve miles in the country. Runs better now, but certainly not back to normal. I guess all the SeaFoam really did was clean out the first five cylinders because I pulled the boot off #6 again and it still makes no difference. At least I was smart enough to get insulated sparkplug boot pliers for this time. ;^)

What do you think? Is there something else I can try to clean up #6? Or is a valve job in my future?

 

[Frank]

Warmed it up. Choke wasn't all the way open so I turned it some more. It's now open all the way and the pointer is straight down :^/

Drove it twelve miles in the country. Runs better now, but certainly not back to normal. I guess all the SeaFoam really did was clean out the first five cylinders because I pulled the boot off #6 again and it still makes no difference. At least I was smart enough to get insulated sparkplug boot pliers for this time. ;^)

What do you think? Is there something else I can try to clean up #6? Or is a valve job in my future?

Your choke is not functioning correctly, it's not releasing as the engine warms. But with it open all cylinders are getting a good mixture, so the #6 cylinder situation is unrelated.
FIRST thing is to do a compression check.
remove all plugs.
Prop throttle and choke fully open.
remove the big coil wire at the distributor end and ground it to the block, or remove the little wire which goes from the coil to the dist, at the coil.
install the gauge and crank over the engine 8-10 compressions on the gauge.
record the reading and repeat.

This is the first diagnostic for the fouled cylinder.

 

[FuzzyDriver]

I was disappointed that some of the plugs could look so bad after a couple warm ups and only 18 miles of driving. Could a choke that doesn't open all the way cause this to happen so quickly?

Here's the compressions in order, #1 to #6: 160 - 163 - 174 - 160 - 149 - 141
and the plugs:

 

[FuzzyDriver]

I remember back in the 80's I had a J-10 with a 258-6. It had a cylinder fail when an inlet-exhaust connecter broke, allowing a rocker to rotate off of a valve. I see our sixes don't have these things, but I was surprised to find adjustable lifters. I thought they were non-adjustable from 1964 on. Anyway, I'm not seeing anything out of place on #6, or any of the other ones.

 

[FuzzyDriver]

Here's an update, then I'm going nite-nite.

I cleaned and regapped the plugs. Per your advice, I reset my points to .019; we'll see what dwell ends up. I also put a little bit of SeaFoam in each cylinder through the spark plug holes (roughly a tablespoon).

Per your assertion that the automatic choke isn't working right, tomorrow, once I have it running again, I'm going to pull the heat riser tube and see if it's sucking air through the thermostat at all. I might return the thermostat to having it just barely closed at 25% throttle (per your previous advice) when cold and then warm the thermostat with my hot air gun.

 

[Frank]

Here's an update, then I'm going nite-nite.

I cleaned and regapped the plugs. Per your advice, I reset my points to .019; we'll see what dwell ends up. I also put a little bit of SeaFoam in each cylinder through the spark plug holes (roughly a tablespoon).

Per your assertion that the automatic choke isn't working right, tomorrow, once I have it running again, I'm going to pull the heat riser tube and see if it's sucking air through the thermostat at all. I might return the thermostat to having it just barely closed at 25% throttle (per your previous advice) when cold and then warm the thermostat with my hot air gun.

Thanks for the info and pics.
Choke- no need to disassemble, it should be warm to touch (the cover) after 1 minute, and increasing to hot fairly quickly. Conversion to electric choke is a relatively simple project which assures accurate and fast choke release. Another benefit is, the air pipe style are inhaling unfiltered air from the end of that pipe jammed onto the rusty exhaust. The air heating the choke goes thru the choke housing, thru a carb passage and is released into the engine at the base of the carb. A potentially rust/dust filled vacuum leak- personally, I'm not a fan. Hopefully you can get the stock style tuned up, but it has to be drawing air and getting hot.

The plugs don't look bad except #3 & #6 which look oily. The others evidence exactly what occurred- a too rich mixture followed by a short time of correct mixture. As an aside, if a I-6 is firing weak on these two cylinders, it will be more noticeable and any vibration more accentuated since these two cylinders fire in sequence.

The compression #'s rule out stuck/burnt valve. the numbers aren't great but not terrible either, you know your valves are seating. #3 is the highest, and that is artificially inflated by a high carbon build up over a long time in that cylinder, based on the plug condition. Accumulated layers of hard carbon on the piston (mostly) reduce combustion chamber volume and increase compression. The most common source of this is oil intrusion thru the valve guides. (I'm a former Chevy guy- I know about this!) There's evidence of oily cylinder, but the high compression rules out rings. That leaves valve guides. #6 is more suspect, it may be ring-oil intrusion there but not for sure.

If this were my engine, I would not consider major component repairs yet. 1) Replacing the valve guide seals and relashing the valves to specs, 2) getting the tune correct, especially the carb/choke scenario and dwell. 3) New oil/filter 4)Drive it normally long enough to determine if other repairs are required. From the compression #'s I'd predict doing the above will cause it to "come smooth" and be acceptably operational indefinitely.

This is merely my nickel's worth.

 

[FuzzyDriver]

I had to replace the heat riser bung and tube due to it being corroded away. After drilling the old one out, I blew air into the bung hole to make sure I didn't suck chips into the thermostat. A large cloud of dust/rust came out. I repeated until nothing came out.

Yes, #3 & #6 were very oily. I went ahead and put all new plugs in even though I cleaned and regapped the ones I took out.

WRT, valve lash. I just watched a YT video where the guy used a simple method for setting lash. He was doing it on a Chevy V8, but emphasized that his method works on all engines regardless of manufacturer or cylinder count. He was spinning the rod with his fingers while tightening until the rod was touching the rocker, making it difficult to move with his fingers. Then he turned the engine some (he went on that using this method the exact rotation amount didn't matter) and repeated the lash setting. He repeated the whole thing until none of the rockers needed to be tightened to make the rod touch. There are lots of repeats to this, but also no real chance of setting too tight with incorrect cam angle. Then he finished up by giving each rocker 3/4 turn, adding that 1/2 turn also works.

Does this simple to perform lash procedure sound like it will work?

BTW, I can move my #6 exhaust rod easily. Perhaps that's why I get such a clatter?

 

[Frank]

I had to replace the heat riser bung and tube due to it being corroded away. After drilling the old one out, I blew air into the bung hole to make sure I didn't suck chips into the thermostat. A large cloud of dust/rust came out. I repeated until nothing came out.

Yes, #3 & #6 were very oily. I went ahead and put all new plugs in even though I cleaned and regapped the ones I took out.

WRT, valve lash. I just watched a YT video where the guy used a simple method for setting lash. He was doing it on a Chevy V8, but emphasized that his method works on all engines regardless of manufacturer or cylinder count. He was spinning the rod with his fingers while tightening until the rod was touching the rocker, making it difficult to move with his fingers. Then he turned the engine some (he went on that using this method the exact rotation amount didn't matter) and repeated the lash setting. He repeated the whole thing until none of the rockers needed to be tightened to make the rod touch. There are lots of repeats to this, but also no real chance of setting too tight with incorrect cam angle. Then he finished up by giving each rocker 3/4 turn, adding that 1/2 turn also works.

Does this simple to perform lash procedure sound like it will work?

BTW, I can move my #6 exhaust rod easily. Perhaps that's why I get such a clatter?

That's not the ideal way to lash. And that will not work if your lifters are solids. A photo of the rocker arms fairly close-up would be helpful.

 

[FuzzyDriver]

There be rockers!

View attachment 1732404334424.png

 

[B RON CO]

Hi, you have the adjustable rocker arms, but you don't know if you have solid or hydraulic lifters. You can tell which lifters you have by pushing down on the pushrod side of the rocker arm. If the rocker arm does not move no matter how hard you push down, you have solid lifters. If you can get the the rocker arm to move down, you have hydraulic lifters. If you have a .016-.018 gap between the valve stem and the rocker arm, you have solid lifters. If you can spin the pushrod on most of the valves, I would loosen the tight ones a little. If that rocker arm clatters after you loosen it, you went too far. Running an engine with the valve cover removed is always fun. Note, if the lifter is not on the base circle of the cam, and the valve is partially open, you will not be able to spin the pushrod. All adjustments must be done with the valve fully closed, and the lifter on the base circle of the cam. Good luck

 

[TrickSix]

Your aluminum engine ID tag is right there by the coil. See if you can get a clear picture of the numbers on it.