Carburetor Questions

[nad]

That's exactly what I have, a divorced choke. But anyway, here's the story. I got new metering rods, got the carb back together, and the truck runs now, but really really high idle. I tried adjusting the screws but it didn't make much difference. The motor got warm really fast too, I don't remember it ever getting that warm so fast. Smells like burnt mud too, but there's no mud on the manifolds or anywhere on the engine.Also, it actually hesitates worse than it did before when you punch it, but the truck has a ton more power when it finally does take off.

Also, when I shut the truck off after driving around for awhile, it like started itself back up and sounded like a diesel truck for like a second, then stopped.

What's causing all this? Any help or advice would be appreciated. Thanks guys.

 

[ryoken]

Well, that's run on, caused by the high idle....

did you adjust the idle speed screw, or the idle mixture screws? You may be stuck on the fast idle cam...

As for the heating up, fast idle will definitely warm you up faster, as will running lean...

I'm sorry, I picked this up late, why did you change the metering rods?

 

[nad]

Snapped one in half while trying to get it lined up in the dark, since I have a crappy place to work on my truck.

I did not adjust the idle speed screw, because I don't think I ever took it out during the rebuild. But I did mess with the idle screws, and it didn't really do much good.

 

[ryoken]

idle mixtures screws should be at 2 turns out.. Be VERY careful playing with those... If you turn them all the way in with just a bit too much force, it will ruin their seats...

Set the idle speed screw on the side... You may be dumping more fuel now that the carb is clean..

 

[nad]

2 turns out from all the way in? Wow, before I took them out they were way out, and I do not understand what is meant by "seats". The instructions say to screw them in till they're almost seated, then back them out slightly.

 

[ryoken]

well, the seats are the point at which the needle closes them off and touchs the orifice.. they are tiny, tapered needles, if you tighten them too hard, you will ruin them.. then that adjustment will never be right..

Not sure which instructions your reading from, but Roe's book says 2 turns out from closed.. has always worked fine for me.. techniqually, your supposed to set them by idle speed.. But 2 is usually right in that area....

Honestly, it's just the idle circuit and they are not nearly as important as many think... They will not affect much in the way of operation.. It's an idle and off idle circuit only..

start by trying to adjust that idle speed on the side...

 

[nad]

Well my instructions say 3-4 turns. Anyway, I turned them in and got the idle lower, smelled like it was burning rich, but when I shut it off, it still had "run-on".

 

[ryoken]

whats it idling at?

 

[nad]

1300-1500 RPM. I just went out and started it again to check, and when I turned it off, it didn't start back up like before.

 

[Randy92782]

i'd say that's way high. think mine runs about 500 but that's low and i like it like that. i'd say around 7-900 is about right

 

[nad]

So maybe turn the mixture screws in more? Or should I mess with the idle speed screw?

 

[Randy92782]

well if you're around 3-4 turns out i'd say go in with the mixture screws

 

[ryoken]

eesh, i hate repeating myself...

1500 is crazy high.. stop playing with the mixture screws and set the idle using the idle speed screw on the side... if thats not doing anything, then it's stuck on the fast idle cam on the other side...

you should be about 750 in nuetral..

 

[Randy92782]

go with ryokens theory. he knows more than i do i'm sure about carbs

 

[ryoken]

hehe, I've only rebuilt over 100 quadrabogs...

actually I did a pair this afternoon...

 

[Randy92782]

kinda figured that. i just go and buy another one

 

[ryoken]

Actually I can get remans pretty cheap these days thru Jerry's marine.. $300.. But I can still rebuild em in about an hr a piece... I was joking with another mechanic today about trying one with my eyes closed...


#1 thing people screw up on em is hanging the needle off the float...

 

[Randy92782]

well i have a very short memory so something would definately be wrong in there somewhere

 

[nad]

Well you should get me a remanufactured one then, ryoken I was going to just buy a Holley from the local parts store, but that sounds like way too much work to set up. What's the deal with hanging the needle wrong?

Also, I can't really tell where my mixture screws are at, since I just put them in there to where the needle points were barely poking through when I put it back together. Then I played with them so much today that I have no idea where they're at.

All this work makes me miss my TBI

 

[ryoken]

Well you should get me a remanufactured one then, ryoken I was going to just buy a Holley from the local parts store, but that sounds like way too much work to set up. What's the deal with hanging the needle wrong?

Also, I can't really tell where my mixture screws are at, since I just put them in there to where the needle points were barely poking through when I put it back together. Then I played with them so much today that I have no idea where they're at.

All this work makes me miss my TBI

well, just adjust them with the truck off... tighten them clockwise till all the way in, then just back each out 2 turns...

As far as the needle... I'm refering to the needle and seat in the float bowl that allow fuel into the bowl.. Most people make the mistake of putting the little clip at the top of the needle thru the one hole at the end of the float arm, and having it go down thru the other hole on the other side.. it's supposed to go thru the one hole and "sit" on the flat spot at the back of the float arm...

What this ends up doing is jamming the needle cockeyed in the seat bore, allowing fuel to just pour in the bowl... You would know if this is happening because fuel would just pour out the vent tube...

What was the truck doing that you decided to rebuild the carb?