Junker turned daily driver.

[Giovanni89]

Get a spare emulsion tube before you start meddling. I did a lot of research on them, and here are the big things that I took away. Holes at the top will lean lower in the rpm range. Holes at the bottom will lean higher in the rpm range. Holes above the fuel bowl level will delay the activation of the main jet because the air can flow through those holes and into the venturi without emulsifying any fuel. Too many holes at the top will lean out the high rpm as well. Holes that are below the fuel bowl level will cause the main circuit to activate earlier and enrich the mixture.
The diameter of the emulsion tube and steps/taper also plays a part in how it acts. Generally speaking, the larger the diameter of the emulsion tube, the less fuel reserve in the emulsion tube well and leaner it will be.
My jetting is far different from anything I have come across, but I feel it runs fairly well. It starts at 100 degrees, or 13 below. Doesn't diesel any more when I shut it off. I've towed up to 3000lbs, cruise routinely at 75 on the highway without having my foot buried in the throttle, and return an average of 22mpg mixed driving with the automatic.
I don't have it written down, but I believe what I am running (although i have a opened up exhaust and undercut valve stems) is a 130 main, 140 or 150 main air corrector. a 60 or 65 idle, and a 170 idle air corrector (I modified my carb to accept main jets as idle air corrector jets) but 170 is the stock size. I also have a 1mm hole drilled in my throttle plate opposite of the transition ports. I could never get the idle right until allowing more air in with the hole in the throttle plate. Otherwise I would have to have the idle speed screw in too far, and it would always diesel.
I think from here I need to reduce my idle air jet to get it to richen up just a tad at highway light throttle cruise, but this will mean enlarging the hole in the throttle plate to get enough air at idle. I also need to lean it out at low rpm heavy throttle which I will most likely try to accomplish with a few extra small holes in my emulsion tube. I am running a stock f50 at the moment.

[geezer101]

If you want to know anything about carbies - ask Giovanni. I'm going home...

I mean, I thought I was a lunatic for jamming my Mikuni Solex under a drill press and drill aligning all of the vacuum galleries and gaskets. And I've managed to get my weirdo 34DATA carb throttle linkages to behave like the stock carb but full props to you sir for tackling emulsion tube mods and to even understand how they fully work.

[Giovanni89]

A lot of what I learned was from trolling the forums and posts from folks like you geezer. I don't know everything, I'm just not afraid to start cutting things up

If you want to know anything about carbies - ask Giovanni. I'm going home...

I mean, I thought I was a lunatic for jamming my Mikuni Solex under a drill press and drill aligning all of the vacuum galleries and gaskets. And I've managed to get my weirdo 34DATA carb throttle linkages to behave like the stock carb but full props to you sir for tackling emulsion tube mods and to even understand how they fully work.

[87junker]

I appreciate the feed back I'm hoping the power valve diaphragm will fix some of my issues. I may have went the wrong way with my jet selections. But I did get the coolant hole drilled and tapped.

20181001_210800.jpg

[Giovanni89]

http://www.performanceoriented.com/p...ance-tuning-2/
Scroll down on this page for a lot of good info on emulsion tubes. I believe this was written for weber side drafts, but the theory should be the same. Definitely do not tackle this without a wideband O2. Small changes can have subtle or drastic effects. You can create a lean hole in your fuel delivery curve that if left unchecked could do damage.
This is a photo of my idle air jet setup. Not shown is that you have to grind some relief in the top cover of the carb so that it will fit over the head of the jet.
A word of caution, bolt the carb down to a drill press or milling machine, and use a depth stop. You are intersecting the idle fuel jet hole. When you break through the cross hole it will lift up the carb and if not bolted down could cause some carnage. You are kissing the top of the idle fuel jet seat, so carnage could mean that you idle fuel jet will not seal rendering the carb body useless unless you can re spot the seat. Use a bottoming tap, and watch from the idle jet hole in the side of the carb body. You don't want the tap to to chew up the idle jet seat, which it will do if you go too deep.
idle air jet.jpg

[geezer101]

Agreed on having an O2 sensor and gauge installed. Helps even with minor stuff like setting the base A/F mixture. You ever tried polishing the throats and cutting back overhangs and ledges in the carb body?

[87junker]

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Dang murphys law got me this evening too.

[87junker]

Shew that's a lot of info to soak up. But definitely explains effect of the emulsion tubes.

[geezer101]

Dang, seen that before A drill and screw extractor might get it out, or drilling it out enough to break out the last fragments of the bolt and making a pass through it with a thread tap. Fingers crossed this doesn't turn into a major headache.

[steve1814]

I had the same thing happen. If you have enough thread for half a turn of a nut, welding the inside of the nut to the thread worked for me. I also saturated the threads with break free before welding. worst part for me was the PO stripped the threads on manifold on the other side and used a bent head bolt tapped up through the bottom to "fix it". That was an unpleasant surprise. I had to tap and helicoil new threads in. good luck with your repair, you've been doing a great job on it so far-Keep it up!

[tortron]

Forget the extractor. It will just snap out if that stud is any tighter than finger tight.
Either put a nut over the reminants, and weld them together and unscrew. Or centre punch and drill out with a sharp bit until the hole is just equal to the threads, then pick them out with a pick.

If you do snap an extractor off, grind it flat, punch it, and drill out with a new cobalt drill bit and retap

[87junker]

Extractor was a no go. Started cranking on it and heard the bad tink sound. It didnt break off but the extractor is junk now. So now its drilled thru and waiting till I buy a tap.

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[87junker]

Could go back to sleep this morning so I went out and threaded the hole and put everything back together. Still waiting on carb parts to get back to my original project.

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[87junker]

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Carb parts finally made it in.

[87junker]

Got everything installed changed some jets helped a little but still to lean while cruising in 4th and 5th and when u get on it to speed up it leans out from 2500 rpm and up til I let out when it gets around 17.0 on my afr gauge.

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[87junker]

Cooler thermostat didnt help either. Still getting hot after about 20 mins. It will cool down once u get moving but as soon as u slow down it will start climbing back up.

[tortron]

Cooling down when moving tells us that either the radiator or fan isn't up to scratch.
I don't recall if you replaced the rad on this, but if not it could probably do with being taken to a shop for rodding out to clear the tubes.
You will probably find that 30 percent of the tubes are gummed up.

Also check that your fan is still in one piece, i.e. it hasn't lost any of its blades, and that the clutch is activating. I.e is it turning at a good speed at idle when the truck has warmed up? If not you may need a new fan clutch, or swap to an electric unit

[87junker]

Cooling down when moving tells us that either the radiator or fan isn't up to scratch.
I don't recall if you replaced the rad on this, but if not it could probably do with being taken to a shop for rodding out to clear the tubes.
You will probably find that 30 percent of the tubes are gummed up.

Also check that your fan is still in one piece, i.e. it hasn't lost any of its blades, and that the clutch is activating. I.e is it turning at a good speed at idle when the truck has warmed up? If not you may need a new fan clutch, or swap to an electric unit

I just fisished flushing the radiator. It didnt look too bad and not a lot of junk came out but the ac condenser was packed with dust and bugs. So it got sprayed out really good. In the process of putting it back now.

[tortron]

I just fisished flushing the radiator. It didnt look too bad and not a lot of junk came out but the ac condenser was packed with dust and bugs. So it got sprayed out really good. In the process of putting it back now.

See how it goes. The stuff that gets stuck in the tubes wont come out from a flush. But if the condenser was packed full it would have a noticeable effect

[87junker]

https://youtu.be/lQfRCI27DY0

Radiator seems to have good flow thru it. And it it ran cooler after cleaning. But I'll have to see how it does on a warm day again it had cooled down quite a bit from earlier today.

[geezer101]

It should cool down when you're driving. It's getting air forced through the radiator by it's own forward movement. It's when you're stuck in traffic that it'll want to heat up. If you get rid of the mechanically driven radiator fan and go electric it will work when you need it, takes a load off the water pump bearings and improves throttle response. Added bonus is freeing up some engine bay room. I used a batch of citric acid powder to flush out a couple of heater cores and radiators, and it did a decent job of breaking up sediment in them. Some guys run it in the engine but I'm not game enough to as it will attack alloy. My intake manifold on my G63B had corroded out and when I cut the cooling chamber cover out from the base of the plenum, chunks of rust fell out of it (presumably came from the inside of the block and got lodged in there)

[87junker]

https://youtu.be/qqRXScQMm6A

It still has a few lean spots but does better at maintaining speed in 4th and 5th.

[87junker]

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A little before and after.

[Giovanni89]

Looking good! Even with a cooler thermostat and a new radiator, water pump, and fan clutch, mine was getting warm at low speed too. Where is your idle at? If I have my park/neutral idle set to 900rpm it drops to about 6-700 in gear. At that speed it just wont move enough air with the stock fan. I tried upping my idle a bit but it really slammed into gear and wanted to pull hard at idle. I went the larger rigid mounted mechanical fan route because I'm cheap, but I'm willing to bet that a good electric fan will solve your problem. I actually tried some little electric fans I had first, they worked well at idle but weren't letting enough air through at high speed. If you go electric, you'll want to upgrade the alternator if you have the 40ish amp unit.

[87junker]

Yesterday day it did good it was 85-90 degrees. Today and tomorrow should tell me how it's doing but I'm afraid the 180 thermostat is gonna be too cold for winter.