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Home » Public Forums » GMCnet » Quadrajet float bowl leak down (To fix or not to fix)
Quadrajet float bowl leak down [message #261394] Tue, 09 September 2014 11:24 Go to next message
An87ttype is currently offline  An87ttype   United States
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I have my carburetor out for a float adjustment and minor rebuild and cleaning. One of the problems many face is the that the bowl leaks down overnight due to a couple of caps that tend to leak the gas out the bottom of the carb. Some fixes are to replace the caps with some that you can find that seal better. Others use epoxy to seal them.

Now that it's out I'm tempted to fix it, but now I'm second guessing doing it. One reason is, I think I like the fact that I have to crank it for a while before it starts. It gets the oil pressure up and the cam wet before it starts. On the downside, I hate smelling the gas as it leaks out.

Any comments on whether or not it worth fixing? Other than the strain on the starter, I'm thinking the benefit of starting it with the oil pressure one the way up seems worth it. What do you guys think...Thanks


1975 Eleganza II Hudson Valley NY
Re: Quadrajet float bowl leak down [message #261399 is a reply to message #261394] Tue, 09 September 2014 14:14 Go to previous messageGo to next message
budworks521 is currently offline  budworks521   United States
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Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
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I supposedly had my plugs resealed from a carb rebuild and still have a hard time restarting it cold. Once warmed up and running it is an easier start. If all that gas leaks out of the bowl it has to go somewhere. From some of the research I did it can get into the crankcase if the rings have wear on them. I hear people saying it is better to have them resealed. Just what I have heard and or learned.

1974 Painted Desert 455 upper half rebuild constant project inexperienced mechanic Grand Rapids Mi Always trying to learn
Re: Quadrajet float bowl leak down [message #261402 is a reply to message #261394] Tue, 09 September 2014 14:21 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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An87ttype wrote on Tue, 09 September 2014 12:24
I have my carburetor out for a float adjustment and minor rebuild and cleaning. One of the problems many face is the that the bowl leaks down overnight due to a couple of caps that tend to leak the gas out the bottom of the carb. Some fixes are to replace the caps with some that you can find that seal better. Others use epoxy to seal them.

Now that it's out I'm tempted to fix it, but now I'm second guessing doing it. One reason is, I think I like the fact that I have to crank it for a while before it starts. It gets the oil pressure up and the cam wet before it starts. On the downside, I hate smelling the gas as it leaks out.

Any comments on whether or not it worth fixing? Other than the strain on the starter, I'm thinking the benefit of starting it with the oil pressure one the way up seems worth it. What do you guys think...Thanks

Daryn,

That leak does you no good at all and wet fuel on top of the engine is a fire risk.

It you want to crank it without firing, just don't set the choke. Crank until you see the gauge lift that tap the throttle to prime the charge and set the choke.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Quadrajet float bowl leak down [message #261438 is a reply to message #261394] Tue, 09 September 2014 19:44 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Fuel diluted oil is worse for the bearings than just starting it. EFI cars start right up and the computer takes them right up to about 1700 and then tspers them down. Yes they have roller cams, but rod hearings seem to be the Olds weak point not the cam lobes. At cranking speeds the walls are mostly dry as you need running RPM to fling oil up ther like the insides of a dishwasher . I run 5w40 wuth this in mind. Very easy to epoxy the carb while out

John Lebetski
Woodstock, IL
77 Eleganza II
Re: Quadrajet float bowl leak down [message #261458 is a reply to message #261394] Tue, 09 September 2014 22:12 Go to previous messageGo to next message
Chris Tyler is currently offline  Chris Tyler   United States
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No Question; fix it.

Easy to do with 5 min epoxy.Remove and clean well first.

I use JB weld mixed with aluminum filings.


76 Glenbrook
Re: Quadrajet float bowl leak down [message #261461 is a reply to message #261394] Tue, 09 September 2014 23:05 Go to previous messageGo to next message
Gatsbys' Cruiser is currently offline  Gatsbys' Cruiser   United States
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Definately FIX IT. You are looking at a pleathura of problems of you don't including failure to start. That is one of the problems I have had and I can't begin to tell you the frustrations it has caused because of various reasons. And if you battery is a bit weak, you are in for a whole new can of worms.
Don't tempt fate, fix that leak while you can or you will be very sorry.
Just my advice.
Re: Quadrajet float bowl leak down [message #261465 is a reply to message #261461] Tue, 09 September 2014 23:43 Go to previous messageGo to next message
Bullitthead is currently offline  Bullitthead   United States
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Fix it. Use high quality epoxy. If you want to crank until until you have oil pressure, put a hidden or unlabeled switch on the power to the coil and don't tromp the pedal before you crank so the choke is not set, like Matt said. Then tell your insurance agent that you have an anti-theft system installed and get a 15% discount on your comprehensive coverage if they offer it!

Terry Kelpien ASE Master Technician 73 Glacier 260 Smithfield, Va.
Re: Quadrajet float bowl leak down [message #261527 is a reply to message #261394] Wed, 10 September 2014 18:43 Go to previous messageGo to next message
An87ttype is currently offline  An87ttype   United States
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Thanks all...I will fix it. My kit arrived today so I should have it done by the weekend.

1975 Eleganza II Hudson Valley NY
Re: Quadrajet float bowl leak down [message #261613 is a reply to message #261394] Thu, 11 September 2014 12:52 Go to previous messageGo to next message
An87ttype is currently offline  An87ttype   United States
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Ok, so I fixed the leak, but while taking everything apart I see that the throttle shaft has a fair amount of play. I know this is a pretty common issue on old carbs, but the question is how much is too much. I know in an EFI system this much play in a throttle body would allow too much unmetered air and would probably be a show stopper. In these old engines I'm not so sure it is a major problem until it starts to effect the operation of the linkage. I did not have a problem with adjusting the idle before. It ran pretty good until it started flooding over, but it may leak a little more now that it's clean.
I suppose I can get a bushing kit and fix that too but I need the coach this weekend so I will have to r&r it a gain later.

Anybody have any quick fixes or experience with this problem?

As usual, thanks for all the comments and help...


1975 Eleganza II Hudson Valley NY
Re: Quadrajet float bowl leak down [message #261634 is a reply to message #261613] Thu, 11 September 2014 18:54 Go to previous messageGo to next message
Bob de Kruyff   United States
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An87ttype wrote on Thu, 11 September 2014 11:52
Ok, so I fixed the leak, but while taking everything apart I see that the throttle shaft has a fair amount of play. I know this is a pretty common issue on old carbs, but the question is how much is too much. I know in an EFI system this much play in a throttle body would allow too much unmetered air and would probably be a show stopper. In these old engines I'm not so sure it is a major problem until it starts to effect the operation of the linkage. I did not have a problem with adjusting the idle before. It ran pretty good until it started flooding over, but it may leak a little more now that it's clean.
I suppose I can get a bushing kit and fix that too but I need the coach this weekend so I will have to r&r it a gain later.

Anybody have any quick fixes or experience with this problem?

As usual, thanks for all the comments and help...


That sloppiness can cause issues with the idle mixture but can also cause the throttle to stick because the butterflies will bind in the bore.


Bob de Kruyff
78 Eleganza
Chandler, AZ
Re: Quadrajet float bowl leak down [message #261672 is a reply to message #261394] Fri, 12 September 2014 05:53 Go to previous messageGo to next message
budworks521 is currently offline  budworks521   United States
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I believe I am having the same problem with my carb. I had everything done as you did and find that my primary throttle plates are not closing tight enough for a quick start on my engine. Also, if I press the throttle linkage forward I have a much easier start with the 455. The plates are hanging up in the bores. Is your flooding issue just related to gaskets being wet or more? Are you seeing any unspent fuel/film/carbon in the intake manifold with the carb off? These are my issues and I suspect it is from the plates binding. I did manage to stiffen my accelerator cable in hopes to get the plates to move better. Could you please let me know how you fared in your efforts on the bushings and if it stopped flooding the carb. thanks

1974 Painted Desert 455 upper half rebuild constant project inexperienced mechanic Grand Rapids Mi Always trying to learn
Re: [GMCnet] Quadrajet float bowl leak down [message #261682 is a reply to message #261672] Fri, 12 September 2014 09:02 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
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Lawrence, I found my primary plates were hitting the front side of the bore
and not allowing the plates to close. There are two screws that hold that
plate to the shaft. Loosen those and see if you have any play in the holes
to allow the plate to clear the front side of carb. Careful you might find
that the screws have been staked to prevent a loose screw from falling into
carb throat.

On Fri, Sep 12, 2014 at 4:54 AM, Lawrence Harrison
wrote:

> I believe I am having the same problem with my carb. I had everything done
> as you did and find that my primary throttle plates are not closing tight
> enough for a quick start on my engine. Also, if I press the throttle
> linkage forward I have a much easier start with the 455. The plates are
> hanging
> up in the bores. Is your flooding issue just related to gaskets being wet
> or more? Are you seeing any unspent fuel/film/carbon in the intake manifold
> with the carb off? These are my issues and I suspect it is from the plates
> binding. I did manage to stiffen my accelerator cable in hopes to get the
> plates to move better. Could you please let me know how you fared in your
> efforts on the bushings and if it stopped flooding the carb. thanks
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



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Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming
Re: Quadrajet float bowl leak down [message #261693 is a reply to message #261394] Fri, 12 September 2014 12:26 Go to previous message
An87ttype is currently offline  An87ttype   United States
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Registered: September 2012
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I put mine back together and it looks like the slop is not enough to cause a problem with the linkage but there is a small vacuum leak. Will see how the idle adjusting goes. If it looks like the vacuum leak is small emough I do not think I'm going to re-bush the shaft. If yours are bad enough to cause binding I don't think you will be able to get away with not fixing it for long. Be careful with the screws that hold the plate. One of those could do a lot of damage if ingested by the engine.

1975 Eleganza II Hudson Valley NY
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