Carter WO metering rod length

[Dutch_Jeeper]

So, i'm rebuilding my carb. It had the leak at the throttlebodyshaft. I had that fixed by redrilling and installing a slightly oversized shaft. Hoping that solved the problem of not iddling without the choke half open.

Allas, that did'nt help though it did run significantly better, the choke still had to be slightly open though? Must be a leak somewhere else. It would also only react to the iddle screw but not the iddle mixture screw, completely in or out no reaction whatsoever? There still seems to be a very tiny leak around the shaft but its a very tight fit and i can feel no play whatsoever, i doubt it can get any better simply because of the construction. It hardly reacts to using brakecleaner to look for leaks. I dont have a vac meter, but it dies instantly when i cover the horn with my hand.

But the adjustment is a bigger problem, i suspect it was not properly adjusted ever with the iddle mix screw but simply only with the iddle screw to set the valve. Had a specialist who also rebuild the shaft for me look at it and he to was baffled why it would not react to adjustments. Fuel pressure was good, fuelbowl height ok, just no response. He did notice the carb was a mismatch and that perhaps it was "repaired" or rebuild using parts from a generator carb and suggested to rebuild it to make sure it was'nt in the jets and valves.

I did get the old carb and some purchase & maintenance papers with the Jeep. Seems they worked on the carb and replaced the main jet at some point according to the papers. That did not seem to help as shortly after another carb was bought. Anyway i decided to follow the advice and rebuild the original one.

Ordered a complete rebuild kit while i took the 2nd carb apart and cleaned it.

While waiting for the metering rod tool to arrive i compared the old and new parts before starting the reassembly. I noticed the new metering rod that came with the kit is longer then the old one in the carb?

I'll do some exact measurements and brand of the kit tonight and post them but it looks like the new one is roughly about 2-3mm longer.

What should the correct length be?

Second question, there is a lot of play (0.5-1 mm radial and 2 mm axial) on the chokevalve shaft which i noticed when i disassmbled it, the shaft is pretty worn� straight through the chrome to the brass. I have not checked it on the carb that is still on the jeep if there is alot of play on that one to. I'll be taking it off tonight.

How bad is a leak at that point, imho should'nt be a problem since its before mixture and installing an openfilter would result more or less in the same thing, ie more air into the horn, simply said??

[Dutch_Jeeper]

So here are the measurements on the new and old metering rod, there was no manufacturer name on the kit, it only came with a few sheets of a Carter WO manual. It is very complete and looks like the Krage motorsport rebuild kit i saw mentioned in one of the Carter rebuild guides. I also received the metering rod tool yesterday so i can start rebuilding.



old:


new:


And the oversized throttlebody shaft, it was a very tight fit when i got it back from the machine shop. It did not move smooth at all, called them back and it was the best they could do, it had to wear in a bit according to them, but to have it operate smoothly it would need a stronger return spring which imho is not the way to go. I disassembled it again and i could not pull it out easily, had to wiggel and pull to get it out. Not good imho cause it might be airtight but with so much friction would probably wear down pretty quickly. Luckily all that was needed was polish the throttleshaft with some P1500 sandpaper. After that it turned and returned very smoothly and i cannot feel any play in the shaft when assembled, radial or axial. You can see the markings on the shaft after pulling it out:





Now i rather have a weeny tiny airleak because of the polishing which i highly doubt, then it wearing down fast because of the tight fit or it getting stuck open when some inevitable sooth starts building up around the shaft. One other thing is that they installed a new valve but that did not close all that well. First i thought they had it facing the wrong way (number towards engine)  but it turned out that the side of the valve was not tappered but straight so it hit the sides of the throttlebody. Put the old valve in and it closed smoothly without seeing any light shinning through.

I'll be taking the other carb of the Jeep tonight and start rebuilding this weekend. Hopefully all goes well and i can get it adjusted properly for next weeks end of the year Jeepclub event.

[scoutpilot]

[size=12] Drilling and going to an oversize shaft is the last thing I would do. The carb was designed to run with the size parts and pieces it came with. Nothing else.  Also. drilling is not as good as reaming to size and setting bushings.
Don�t use brake cleaner to check for leaks. Use starting fluid or unlit propane. The brake cleaner does not react like the other two.
Acquire a vacuum gauge. Learn how to use it. Here is an excellent primer; http://www.secondchancegarage.com/public/186.cfm
I am concerned that the wrong carb kit may have been shipped to you. Or the wrong parts are in your carb to begin with. 3 23/64�  (8.53281cm) is the correct length for a 636SA. Which carb do you have?
Play in the choke shaft is as you said. Not as much of an issue. Unless the plate catches on the side and won�t open/close easily.[/size][/b]

[Dutch_Jeeper]

Thank you Scoutpilot,

Drilling was the best option, i did suggest using bushings but according to the guy i talked to, redrilling and a oversized shaft was the best way to go and how they always do it. There are not many carburetor shops over here and the ones i called all said the same thing.

The one man shop close to where i live is one of the biggest WW 2 Willy's & Dodge parts vendors and also runs restauration & maintenance. Everything he said so far made the most sense compared to the rest and consistent with what i find on this site, G503 and your excellent website. He also suspects the internals to be wrong to start with and noticed the carb is a mismatch, i got the rebuild kit from him and it is the only one available, at least over here.

I'll get some more detailed information tonight when i pull the one on the Jeep and compare the numbers. Knowledge on the carter is not as extensive and widespread over here as in the US and talking with a few people it seams the general consencus is, does'nt matter, get a old WW2 willys carb they are all the same use what you need to build one good carb.

That i suspect is what happened with (both?) I know for certain that i have at least 1 636s throttle body (stamped 505) though that does have the 596 3 armed linkage opposed to the "2 piece" linkage that should be on a 636s!?

The other one i suspect to be an original 596 throttlebody (the switched carb by the previous owner) since it also has the 3 arm linkage, but i did not pay attention to the number i will know for sure when i see the numbers stamped in it tonight. Of the top of my head both bowlcovers have 12 patents stamped on it, not sure about the cover with the manufacterer name if either one has a C or numbers.

As for the metering rod lengths!? That would mean bot are between 4-5 mm to long as what it should be? Makes me wonder what length the one still on the jeep is.

I'll post the numbers tonight and see if we can come up with the best parts,if possible at all, to build one good carb  If not, i'll dump both of them in a box with all the parts and send them to you Scoutpilot 

[Dutch_Jeeper]

Okay, pulled the carb from the Jeep and for clarity, i had the throttle body of what had to be the original carb (the on i got extra with the Jeep) refurbished with the oversized shaft and used that.

That throttle body is stamped 505 and a B so it's a 636s!? It had the 3 linkage but that was replaced with the "2 piece" throttle linkage so should now be correct!?





This is where it gets interesting, The carb on the Jeep did not have any patentnumbers stamped on the fuel bowl

The throttlebody (which i replaced and the one that was on it when i got the Jeep) Has no numbers stamped on it, just a number on the side!?







The cover on the no patentnumber fuelbowl was from a late model:



The cover that was on the other carb (the extra one i assume to be the original one) is from an early model:



The metering rod that came out of the carb on the Jeep is the same length as that from the 2nd carb, so the 2 old ones are the same length. Numbers on them both are 75 - 547

So i think i will be using the patentnumber bowl, the late model cover, the rebuild 505 stamped throttlebody, and the airhorn i already cleaned with the best of the 2 chokevalve shafts, the only difference between the 2 airhorns i have is that one is stamped with a circled C and the other has no marking at all. I think those are the parts the previous owner switched between the 2 carbs!?


That only leaves me with the question what to do with the metering rod?

[scoutpilot]

[size=12]75-547 is the correct part number for the metering rod. Your concern should be that the length is correct (3 23/64�  (8.53281cm)) and that the tip measures out at .047� or better.
Let us know how it turns out.[/size][/b]

[Dutch_Jeeper]

Well it's on and she runs great, took 5 seconds to let the fuel into the carb and she fired right up. I first went to the shop this morning with all 3 metering rods to see if he had another one. All were the same length and number 75-547, though i think i'm making a measuring error. Ar you talking total lenght of the metering rod should be 8.53281 cm or measured from the center of the eye to the tip? If i do that last measurement i do get very close to the 8.53281 cm length?

Anyway since there's no quick solution i decided to put one of the old ones back in and adjusted the pump and rod with help of your video on youtube :-) Thanks for that very educational video Scoutpilot.

All seems fine and the carb reacts to all adjustments i make, Idle mixture, idle and choke. If anything, she now does not run or start with choke fully open, simply runs way to rich, once it's on temp pulling the choke she starts dying from to rich mixture. I have not taken her out for a spin yet since i had a couple of beers while working on the carb and adjusting it :-) I'll take it out tomorrow but i'm very hopefull it's ok and only a little bit more finetuning is needed. Also got a can of starting fluid and there are no leaks, i think it came from somewhere else last time i checked before the rebuild. The throttle shaft is good and solid.



https://youtu.be/fWf4IMIO7l8

[scoutpilot]

[size=12]I do hope all goes well tomorrow. Good Luck![/size]

[Dutch_Jeeper]

  Sounds like you have some serious doubts of me making it to the end of the street Scoutpilot  and probably your not far off since, Ahum my middlename is Bubba  , I am however very confident it all turns out ok  there's enough ductape and wd40 under the passenger seat to make it home 

[scoutpilot]

[size=12]I have no serious doubts. The Duct tape will get you home.� [/size][/b]

[Dutch_Jeeper]

Well i made it to the end of the street and beyond 

Starting has improved by miles and also idle is fine and for the first time very smooth and steady all the time, needed a bit of tweaking on route to set the idle a bit lower. I notice a real difference on the lowspeed power, picks up very smoothly after rounding a slowspeed corner and accelerating away in 3th. Lots of grunt at the bottom end, something now very noticably improved because before i did not know any better.

2 things remain i will have to look at:

On the high speed end it feels to come a bit short, from 65 to 80 kmph it takes longer to reach 80 and i have to full throttle it, it gets there but it takes more, it went there alot better before the rebuild. Off course it's not a speed machine, it never was, but what i notice increased on the low end now seems to be missing more on the high end.

2nd when slowly pulling away with just a bit off throttle it first wants to die before picking up. This is just for a second on initial movement of the throttle after that it never lacks.

Probably need to do some readjustments to the pump and metering rod, first time so i might be a bit off on the initial measurements. I'll make an appointment with the guy who helped me before to have it set up better.

All in all a fun thing to do and not difficult at all in the end.

[scoutpilot]

[size=12]To get rid of the stumble all you have to do is raise the metering rod slightly. Just ever so slightly.
[/size][/b]

[Dutch_Jeeper]

  thanks Scout, adjusted it ever so slightly, and it worked, still has a little dip but already alot better, it just needs another ever so slightly :-) Never thought the metering rod was that sensitive to adjustments. But i'm getting there 0.001 millimeter by 0,001 millimeter 

[Dutch_Jeeper]

Update

Runs like a champ :-) Did some teeny weeny ever so slightly adjustment to the metering rod in the field and probably because of alot of luck only got it spot on 

Last weekend we had the last Jeepclub Netherlands event, had a 140 kilometer highway drive ahead of me. Still lacked at the top end, did the adjustment by hand after 50 kilometers of highway driving and barely able to get it to 80 kilometers an hour.

After that teeny weeny ever so slight adjustment, the dip was gone, still had the low end grunt and would happily go to 90-95 kilometers per hour if i pushed it. I do not have a overdrive so taking it to 95 was just a test. The Jeep feels and sounds best doing around 85km/h tops, Hand throttle out, cruise and be happy.

It was an event on a Dirt bike track, day before we explored the track and marked the the trials, some were a bit to much for my XJ  But the next day the CJ3 made it through like it was just a speed bump whaha.

My XJ



Oooops 



As marshalls guiding people new to off road driving we always tell them to prepair, You know the basics, like know where your tow point is, attach a shackle and rope to it before you go off roading etc, etc, lol lol well you know the drill  off course that's just for the newbies lolz



My buddy had no problems whatsoever with that mudhole lol



This dirt bike track is in a part of the Netherlands with a sandy surface, but the Netherlands being a river delta, sand can mean anything from a torential rain coming down and soaking up all the water leaving no mud at all within minutes, to sticky clay slick as ice bogging down any vehicle no matter how extreme and top dollar within yards only being able to go forward with a winch to a kind of dry looking sandy surface actually being somekind off yoghurt substance or milk cream. No matter how big your wheels are no mattr how much horsepower, no mattr how build your Jeep is, you will get stuck. Unless apparently as i learned this weekend you have a lightweight Willys on narrow tires lol 500BHP 38 bogger tires Jeeps struggling to get up a hill in the yoghurt mud and the CJ3 steadilly overtaking you  offcourse at some points ground clearance is a problem, but lol i'm so happy with it. just 2 things i need, a selectable locker would ne nice on some occasions and a overdrive for the highway. Apart from that and staying away from the most extreme trials, i drove past Croatia Trophy trucks stuck deep without a problem.

Just a few pictures, more to come:

[scoutpilot]

[size=12]BRAVO![/size][/b]