Rebuilt carb ----> Gas leak! (UPDATE)

[jode]

Well, I just typed up a huge topic on this and inserted one image. when I hit submit, it siad I couldnt submit more than 8 images and when I went back, the text was all gone....boy does that suck....sorta like the fact that my carb is leaking gas like a seive.

I'm going to try to attach a pic of what the carb base looked like after I pulled the carb but if it dont work, try this http://www.fmtc.com/~wagenmann/Jeep/Joe/Carb.jpg
http://www.fmtc.com/~wagenmann/Jeep/Joe/Carb.jpg
Anyway, it looks like there was some gas leaking across in between the barrels on that plate...today after I reinstalled my freshly rebuilt carb (rebuilt courtesy of 1BAD401 and his dad who spent the whole day helping me rebuild it (it was over a 320 mile roundtrip to Travis' dad's house where we did it)) i fired it up and the engine was loping real bad...it loped for prolly 20 seconds before the idle smoothed out (I assume that this was while the bowl filled with gas) and when it finally smoothed out...it started dripping gas like a mother out of the front area of the carb. :eek: :mad: I am assuming it is a bad hose where the fuel filter connects to the carb, but I am starting to wonder if somwthing else might have contributed.
One of the things we discovered in the rebuild was the the DSPO had cranked the lean/rich knob out so far that the choke was rendered completly inoperable. (Also the needles were frozen in the down position). Is it possible that the PO had cranked that knob down because this carb was overflowing or something? I really couldnt tell where the gas was coming from, but it seemed like it was everywhere quick with the major concentration right at the front near that brass fitting where the fuel line goes intot he carb. I'll replace that on monday and re-teflon the brass fitting's threads, but is it possible that the gas leak is partially coming from under the carb at the junction of the carb body and the intake manifold's base? It seems to me that any gas coming from that area should be pretty dern low in quantity....or is it possible? Anybody got any thoughts on this?
Hopefully what will happen is that monday after doing the hose and the brass fittings, it will be problem - solved, but just in case that doesn't happen, what are some of the crazy things y'all have seen carbs do relating to gas leaks that might help me in my situation? Suggestions?

BTW
I'd like to dedicate this space to a special shoutout to my homie 1BAD401 and to his pa. You two deserve the FSJers of the month award :D
Don S gets a honorary mention because he offered to help me rebuild the carb too...it was the whole idea of trying to get a gas-y carbuerator on a commecial airline to bring the carb to TX that made that not work out so good....thanks anyway... smile.gif

[ November 24, 2002, 05:24 PM: Message edited by: jode ]

[Cowboy]

during the rebuilding process you didn't find any cracks (like in the bowl) or any spots where the carb was corroded badly? What kind and model # was the carb?

[1BAD401]

Joe:

If it's coming from the fuel line coming into the carb it might need to be re-telfon it and tighten it up. If it coming from the top plate of the carb we have a problem, remember the time my Dad had with a couple of bolts that the PO had screwed up, the might be a problem.!!! Try to re-tighen every thing, don't wrench on them to much, or you'll have more problems.

I'd bet the the gas leak is coming from the inlet and just needs to be tighten up. The real lopy idle has me though, it shouldn't be like that, did you set your choke when you first started it? How was the choke idle, was it high or low rpm? After it warmed up how was the idle and throttle response?

[jode]

Motorcraft4350
no cracks or corrosion was detected.

I certainly hope that it is just that the threads need tightening or that the hose was cracked, but I wasn't able to tell where it was coming from. I checked the bolts/screws holding it all together and they seem to have good tension. I'll do the threads and hose on monday and give a report.
As far as the lope-y idle, that seemed to go away after 20 seconds or so...it was prolly just doing that as the carb bowl filled. Unfotunately, there was no time to "let her warm up" becuase there was gas dripping like a sonaofagun. I had to shut her down (I was moving a lightspeed to kill the ignition) after only 20-30 seconds of running. When I left her, there was a puddle of gas in one f the indentations on the intake manifold :eek:
And yes I set the choke and (after the carb finally got some gas) it was running great! It has never run like that immediatley following a cold start! I am exctied to get this gas leak fixed, cause I can tell she is in lots better condition now than before smile.gif

[Don S]

Originally posted by jode:
Motorcraft4350
no cracks or corrosion was detected.
I am exctied to get this gas leak fixed, cause I can tell she is in lots better condition now than before smile.gif ..
jode:...
It is with a heavy heart.. :( .. that I have to inform you of my thoughts…
... IMHO... the odds are the top of the carburetor is warped in the area where the fuel comes in. Mine is warped and I’ve heard of others with the same problem.
... I started building up the surface on the main body for a fit to the warped area but found an MC4300 and fell in love with it.
... If you still want to come by the 'Brave Heart Mansion'(we live on William Wallace St.) during your Lone Star visit let me know…
Good Luck. ;) .CUL… ds..
- - - - - - - - - - - - - - - - - - - - - -
76 406 QT TruTrac 2"lift 31x10.50s been over 261 Colorado MTN Passes since '85-BRC#30093 http://www.sharetrails.org/ –Join and save your Trail
http://www.fullsizejeeps.com/jeeps/files/1963-1983-Wagoneers/76snorL.jpgJeep of the Month http://www.auburn.edu/~hawkijf/test.html
http://communities.msn.com/ATexasOklahomaJeepClub/yourwebpage.msnw ..
2003 Ouray Invasion tips ABOVE*&*Abbreviation & Acronym list BELOW
http://groups.msn.com/ASW4x4CampingTrailTravelClub/abbreviations.msnw

[1BAD401]

Don S:

You might be right on this, when we took the top off the carb a couple of bolts where snug and some where really tight. Two of the bolts were different, they should be phillips head and they were flat head. On the two that were flat headed they also were difficult to tread in.

Joe:

Just make sure that the fuel inlet is tight, if this is a little loose you will have fuel all over the intake. (been there done that) Start the Jeep and run the throttle from the side of the carb, you will beable to see exactly where it coming from. Just pray the top of the carb isn't warped! If is it you should see fuel seeping out the top gasket. Also you can run it without the air cleaner on (while adjusting), not sure if you started it that way.....(just don't backfire!!!!) :eek:

[jode]

Well, I guess the votes are in...I am officially screwed. *&^*&^)^*&#$*&#)!!! redface.gif

I just came in from working on the carb. I got the drip stopped (it was a combination of leaking hoses and the brass fitting where the fuel goes in. That is the good news. The bad news is that it is still seeping redface.gif . I am screwed. Reading the above two posts has confirmed in my head that the dadbern POS is warped. It is seeping right out under the front of the carb and I think I can almost see the gap in between the gasket. ARRRGHHHHHGHHGHHG (*(&$)(*#)(@#$*&%(*&#)($*%(*#
Now what?
DS, you got any lines on a new carb for me? (now that I just dropped $30 into a rebuild on this one redface.gif )

Yeah, I may still try to drop by your place whilst I am in TX...would be fun to put a face with the name....we'll have to see what the schedule is....

ANYBODY GOT A USED CARB THEY WANT TO GET RID OF (for free)?
:(

[Lugnut]

Are you sure the needle and seat are sealing? With THAT much gas coming into the bores it sure does sound like the needle/seat just are sealing properly, in fact, sounds like they may be jambed in the open position. Have you looked to see if they are working freely?
1. Pull the top cover of the carb off,turn the top cover upside down and see if the needle contacts the seat properly, that there are no obstructions or anything hampering it's free movement.
2. Unfortunately, these carbs have a few shortcomings, weeping of gas between the top cover and the main body is one that comes to mind. I contacted a company in Calif. who specializes in rebuilding carbs. and they quit rebuilding these carbs because they felt they couldn't guarantee they wouldn't leak and be a potential fire hazard.
Sorry to offer you such poor news about these. I've been using one I carefully rebuilt about a year ago. I have had it back apart a couple of times since then with a problematic accelerator pump problem, and still haven't fixed it. It continues to have a flat spot in the acceleration because the pump is just not working properly and probably never will.
As for a couple of the screws being straight slot screws and the rest being phillips, this is common. I have two of these carbs and they both have this arrangement. It's been a while since I had mine apart, but, as I recall, these two types were different for a reason. Sorry, just don't recall what it was.
I even went so far as to order an adapter from Jeg's or Summit to adapt my manifold to use the more common Holley 4-bbl config. but I've since learned my county is going to be testing tailpipe emissions in a couple of years and I know the Holley won't pass. I have a parts vehicle with a 2150 Motorcraft on it which I'll be swapping along with the 2-bbl intake.
Sorry, I can't sound more encouraging in your situation.

[1BAD401]

Joe:

Try to loose'n all the bolts on the top of the carb, the part that you think is warped, tighten that down. Work your way around the rest of the carb, make sure you do a star pattern when you tighten them. (like with lugnuts) This might help!!! $400 for my brother wag and you can have Edelbrock Intake, headman headers and lost of good parts to sell!!! smile.gif Sorry that things didn't work out!!! :(

[KivaKid]

I'm working out some issues with my 4350 that I just had *professionally* rebuilt. Keep us posted!

[letank]

IF it is seeping.... still.... i agree w lugnut.... the needle may not be seating properly.... even if the base is warp.... this is "just" a major vaccum leak.... as for warpage.... a new fiber gasket could help... but as 1bad401 says: loosen and try to retighten...... lightly tight..... a few turn pass contact.... when it warms up.... then you can check for tightness

you already fix the inlet....

Keep up

Michel
74 wag

[jode]

Can anybody explain how loosening the bolts is gonna fix a leak?

I had a suggestion to try stacking two gaskets on each other....what do y'all think of that?

How about RTV...will it get disolved in gas? ANy cautions against using (a very small amount of) it?

[64Trvlr]

Originally posted by jode:
How about RTV...will it get disolved in gas? ANy cautions against using (a very small amount of) it?Do NOT use RTV in or on your carb.
:cool:

[Don S]

Originally posted by jode:
Can anybody explain how loosening the bolts is gonna fix a leak?

I had a suggestion to try stacking two gaskets on each other....what do y'all think of that?

How about RTV...will it get disolved in gas? ANy cautions against using (a very small amount of) it?..
jode...
... I just dug out my MC4350 to check it and see if 2 or 3 gaskets might seal it up. Guess what … It ain’t warped!! :confused:
... Pardon me but DILS (Do I Look Stupid)… (Please don’t answer that) the top checks out OK yet I know it was FUBAR (warped)in 1988. IMHO the large boss (chunk of metal) in the casting where the fuel inlet is will continuously expand and contract at a different rate than the adjoining area with less bulk.
... These carburetors have for years been subject to wild temperature changes. The pressure, while being bolted together, of the gasket may have, and probably did cause it to warp up and away from the gasket. Add to that theory the fact that the accelerator pump spring may be applying a lot of pressure in the same area.
... Now… if I can believe all that, then how did it un-warp its self just sitting around unbolted for 15 years?? Well dear hearts, my theory is, the aging of the … OMG… I see you all have fallen asleep… :eek: sorry that I have bored you folks… :rolleyes:
... Anyhow I love my MC4300. :D … and I will experiment with the MC4350

Jode I sent you a PM…

Good luck ;) and CUL… ds..
----------------------------------------------
76 406 QT TruTrac 2"lift 31x10.50s been over 261 Colorado MTN Passes since '85-BRC#30093 http://www.sharetrails.org/ –Join and save your Trail
http://groups.msn.com/isapi/fetch.dll?action=MyPhotos_GetPubPhoto&PhotoID=nIgAAAI4JqH2Ksz*nK5VJBwdYFUSEpR9kgKNYAbNSM xIpFdfjx98wr79lCDjSYm5!E0yuchGUqNsJeep of the Month http://www.auburn.edu/~hawkijf/test.html
http://communities.msn.com/ATexasOklahomaJeepClub/yourwebpage.msnw 2003 OURAY Invasion tips ABOVE & Abbreviation - Acronym list BELOW
http://groups.msn.com/ASW4x4CampingTrailTravelClub/abbreviations.msnw

[kidatforty]

I have'nt had experience with that particular carb. but can't you lap/file the high spots down? Double gaskets don't usually work and no question-no silicone. Fuel seeping out at base gasket usually indicates poor needle/seat and warped base on carb./lousy gasket/lousy fibre spacer. If you get it running well enough to idle , spray WD-40 or other spray lube generously at base gasket area and if the idle changes then you have an intake leak.

[jode]

Actualloy, the major fuel leak now (the one that has me out of commission) is not a leak at the base of the carb. It is a leak between two halves of the carb that seal together to create the bowl. Previously, the needles were completly stuck (frozen in place) and it took some serious doing just to get them unstuck. We were fairly careful in reassembly to not mess them up. If, from the picture posted above, you think that the base gasket was leaking, then that is a separate problem (which at this point is minor in comparison).

Anyway, so RTV is out, is there any product out there for sealing up gas leaks? I am getting desperate here. I may end up JB welding the POS if I can't figure something out. What do you think a junkyard would charge for one of these?

Don S. i'll give you a call once we get to TX
BTW, 15 years and you still have an old carb sitting around? Wow, you must have a lot of "stuff" around your house :D