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Discussion Starter #1
Hey guys i dunno if you have seen some of my previous threads but i am having trouble with my bronco idling rough, blowing black smoke out the exhaust and covering brand new plugs with soot (and on a few plugs oil). I'm assuming its running rich. I'm working with the choke right now but i went ahead and checked the slack in the timing chain because i read on here somewhere that that could cause similar problems. Anyways i used the procedure that i believe sigepblue(sp?) suggested. It comes out to be between 6-8 degrees of slack in the chain. I bought this used so i have no idea how many miles are on the engine or when/if the timing chain has ever been changed. So my question is could this amount of slack be causing my problems or should i just stick with the choke adjustments.

By the way i just did a carb rebuild and it did this before the rebuild and now it is doing it after.

I also did a search for this and couldn't seem to find an exact answer so if i overlooked a previous post with this info in it i apologize beforehand.

Anyways any info is appreciated.
 

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what is your air fuel mixture screw set at?
 

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Discussion Starter #3
before i pulled them from the throttle plate, i screwed them in 1.5 turns each until they touched and i applied the same when i reinstalled w/ new o-rings.
 

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OK, just to be sure we are on the same page, this is what you adjusted, right?

If so, then you may need to adjust it some more. 1.5 turns is a good starting point. If you turn it in while the engine is running it should kill the motor.

A way to fine tune it some more is to hook up a tach to the motor and adjust the air fuel mixture until you get max RPMs while at idle. you may have to turn the idle down during this procedure. It is the way I adjust carbed motors now. Also what is your timing at?

I don't think your timing chain is the problem.

Regarding your choke, when it is at operating temp it should be wide open.

One thing you could try, is when the motor is at operating temp, turn the choke adjustment part and adjust the choke so that it is just open when at operating temperature, if you know what I mean.
 

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Discussion Starter #5
I believe that is what i adjusted, (the idle air mixture screws right?) except mine were behind plugs in the throttle plate. Just to let you know this is my first carbed vehicle(minus the go carts and lawn mowers i worked on as a teenager) everything else i have worked on has been fuel injected so this has been a learning experience.

As for turning it until it kills the motor, probably a stupid question, but do you want this to happen? or are you just saying this will probably happen if i adjust it while the engine is running.

When you talk about fine tuning is where i get a little confused. Like which do i start with i know i am supposed to be around 700 800 rpms but by which adjustment? Thats probably where i need the most instructions at. The timing is at the stock 10 degrees before tdc i believe. i will know more when i get ahold of a timing light.

As far as the choke i have let it run for about 15 mins and it is about a third of the way open and i believe this is close or just below operating temp.

The only adjustment i have on the choke is screw in the diaphragm cap that pushes on the diaphragm under vacuum. The actual choke cap doesn't twist like on other electric chokes. it has a notch in it that sits it in one position. Now that i think about it the rebuild kit had a bunch of gaskets in it that seem like they could replace the orange plastic gasket/spacer that had the notch in it. Should i replace the orange with a gasket so that i could rotate it?(i never thought of that)

But anyways sorry for the long post haha i just started rambling there for a bit.

As far as the lawnmower tinkering.. its funny to watch a friends 50 year old dad have the crap scared out of him and almost run into a garage wall because the governor is ripped off, the throttle was wide open and 1 foot flames were coming out of the muffler when he cranked it up and put it in drive.
 

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Lick my balls
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As for turning it until it kills the motor, probably a stupid question, but do you want this to happen? or are you just saying this will probably happen if i adjust it while the engine is running.
That's exactly what I was saying.

The fine tuning:
With a tach hooked up, if you turn the air fuel screw in the RPMs will drop. If you turn it out, the RPMs will rise.


The choke adjustment:


This is the thingy I was reffering to to adjust your choke. After 15 minutes your choke should be fully open. Loosen those 3 screws and rotate the cover until the choke is just opened. See how that works for you.
 

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Discussion Starter #7
okay cool, do i need to set the idle rpm with the idle control screw at the throttle linkage?

I see what you are saying with the choke but mine is different and the way it is set up now(which is the way it was set up when i bought it) it isn't supposed to be able to spin.. i will try and get some pics to show what i mean but the main choke housing has a female notch the plastic orange disc/gasket/spacer has a male notch that fits in the female notch on the main housing and another male notch on the other side that fits into a female notch on the choke cap so basically preventing any twisting unless i just remove the orange disc and put a regular gasket(that the rebuild kit came with) in there so that i can twist it. whew.
 

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Discussion Starter #8
here are some pics to show what i was talking about:

you can see the notch on the bottom of the choke housing



you can see the notches on the orange locking gasket



you can see the notch on the choke cap



this is how the orange locking gasket attaches to the choke cap


i don't have a picture of it but the tooth on the other side of the locking gasket locks into the notch on the choke housing thus preventing twisting. what i was going to try is to replace the orange locking gasket with one of the felt gaskets from my rebuild kit and thus making it adjustable. That should work i think. Do you see any reason why that wouldn't work?
 

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umm well back to the queston on timing chain. if you are going to the trouble to take the cover off and check it, why not replace it?
 

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here are some pics to show what i was talking about:

you can see the notch on the bottom of the choke housing



you can see the notches on the orange locking gasket



you can see the notch on the choke cap



this is how the orange locking gasket attaches to the choke cap


i don't have a picture of it but the tooth on the other side of the locking gasket locks into the notch on the choke housing thus preventing twisting. what i was going to try is to replace the orange locking gasket with one of the felt gaskets from my rebuild kit and thus making it adjustable. That should work i think. Do you see any reason why that wouldn't work?
I've never seen it like that, it's stupid, it has to be adjustable. That is clear since your choke will not open all the way right now. I was going to say just file the notch down on the carb side, but if you have a replacement piece handy, just use that. If the other piece wont work, you could always eliminate the orange piece and fils the notch on the outer case alone, if you know what I mean.
umm well back to the queston on timing chain. if you are going to the trouble to take the cover off and check it, why not replace it?
He hasn't taken the cover off, otherwise I would have told him the same thing, besides the flange is removable on that shaft:goodfinge:histerica:histerica:histerica:toothless:rofl:
 

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Discussion Starter #11
yeah i'll figure out something to do about the locking gasket. and i will also work on the idle issue w/ the air mixture screws. Also how can i tell if i have blown a power valve without pulling it out of the carb? Because it backfired when i shut it off last time i cranked it and i'm pretty sure it came from the carb. But i probably need to get a aftermarket tach b/c my "rpm ear" isn't tuned to v8 yet.

I was gonna ask about the flange and shaft thing you were talking about but i searched and found your "discussion" on it. Lemme just say that i haven't used a retainer on my shaft since my wife got her tube's tied. :toothless :chili:
 
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