Rochester Carbs...
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 38
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From: Flowery Branch GA
Rochester Carbs...
I have rebuilt other kinds mostly older Fords but never a Rochester... I have the kit and there does not seem to be a lot of parts to replace. This is on a 80 model and the mechanic said that it was leaking around the valve seat. Any help would be great. This is my daily driver so I cannot afford for it to be down for long. The wife does not like me taking her car for long.. Thanks in advance..
Steve
Steve
Le Mans Master
Joined: Aug 2006
Posts: 7,431
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Welcome!
Not sure what you mean 'leaking from around the valve seat'?
here's a how to: www.4wheelnoffroad.com/qjet.html PG.
here's a how to: www.4wheelnoffroad.com/qjet.html PG.
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 38
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From: Flowery Branch GA
I think the mechanic was refering to the needle valve seat on the float. It leaks down while the car is not running. Then it is flooded when you go to start the car.. Also when the car sits and idles you can smell gas and it acts like it has a miss.
Racer
Joined: Mar 2008
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Lots of forum members rebuild their own carb. There are some books out that deal with rebuilding your Rochester, you should pick one up and look through it to determine if you want to try it. Many years ago I even came across a VHS tape that was step by step. There are also forum members out there who will rebuild your unit for you. Honestly, I haven't taken one apart in probably 2 years. I would have to start the rebuild on a Sat. morning and with cleaning time and all the interruptions 
, I wouldn't have it back running and adjusted until Sunday.
If you decide to try it yourself, keep posting questions, many have been there!
, I wouldn't have it back running and adjusted until Sunday. If you decide to try it yourself, keep posting questions, many have been there!
Race Director
Joined: May 2006
Posts: 18,756
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The Rochester is notorious for leaking well plugs. If you dissassemble the carb make sure you test it before reassembly. They typically need a coating of epoxy to seal them or drilled, tapped, and a screw inserted with expoxy.
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 38
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From: Flowery Branch GA
Thanks for the info. I have taken it off today and will attempt to rebuild tomorrow. It does not look that intimidating. Worst case I have to go to Summit Racing in lower Atlanta and get another one. I will keep you guys updated. By the way what is a "well Plug"?
Thanks Steve
Thanks Steve
Melting Slicks
Joined: Mar 2006
Posts: 2,465
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From: Orange Park Fl
The well plugs are the things that poke out of the bottom of the main body, and they don't usually leak on 1980 carbs. Early Q-jets had problems with well plug leaks, but they fixed that and leaks on later carbs are rare. The rebuild should be fairly straight forward,
Disassemble (don't remove any of the butterflies). Seat and count/ record turns on all adjustments.
Soak it in lacquer thinner and blow compressed thinner and or air through all passages. Scrub it good with non-plastic brushes.
Re-assemble with the new parts from the kit and re-set all adjustments.
99% of the time that will do it.
God bless, Sensei
Disassemble (don't remove any of the butterflies). Seat and count/ record turns on all adjustments.
Soak it in lacquer thinner and blow compressed thinner and or air through all passages. Scrub it good with non-plastic brushes.
Re-assemble with the new parts from the kit and re-set all adjustments.
99% of the time that will do it.
God bless, Sensei
Last edited by a1sensei; Sep 8, 2009 at 09:16 AM.
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Team Owner
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From: Crossville TN
Since you are presently experiencing leakage from the fuel bowl, it would be a good idea to test it out before you button it up. [If the needle valve/gasket are leaking, your new ones will fix your problem; but if the well plugs leak or you have some porosity in the casting that opened up, a rebuild will not fix your leak.] Just install the needle valve seat/gasket, then install the needle valve/float/hinge assembly. Use your thumb or some weighted piece to keep the float hinge-pin seated, lift the float until the valve seats, then fill the bowl with water (you can use gasoline, if you want, but water will work...and it doesn't burn). Then just let it sit a while to see if there is any leakage. Remember, you don't need to fill the bowl completely, just enough to keep the float raised to seat the valve. If it seals tight, empty the bowl and blow out any water or fuel. Then complete the rebuild. Good luck.
P.S. Oops! you've got to plug off the jet orifices, too.
P.S. Oops! you've got to plug off the jet orifices, too.
Last edited by 7T1vette; Sep 7, 2009 at 11:36 PM.
Racer
Joined: Mar 2008
Posts: 428
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Besides soaking the carb, I also take a can of WD40 or the very least carb cleaner with the plastic spray tube attached and spray into the all of the orifices. This will check for flow to make sure they are still not partially blocked.
It' a really good idea to epoxy those plugs! You got good advice.
It' a really good idea to epoxy those plugs! You got good advice.
Le Mans Master
Joined: Aug 2006
Posts: 7,431
Likes: 1,561
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
When you install the float needle pull clip make sure it is on the end of the float NOT thru the two holes. PG.
Race Director
Joined: Dec 2004
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a1sensei is right. You shouldn't have any problems with the wells. Though, you might want to give them a few light taps with a small hammer to make sure.
If you are going to glue them, keep WD40 away from those well plugs.
Any fuel, oil, WD40 or any other contaminant will keep the epoxy from adhering properly and sealing up the leaks. During our remanufacturing process, we boiled the bodies out in a caustic acid bath before gluing, so we didn't have any problems there.
Also, use steel epoxy or JBWeld. Regular epoxy tends to break down after a while from the heat. You will need to let the glue cure for 24 hours before use, unless you get the JBQuick. It is good to go in 3-4 hours.
If you are going to glue them, keep WD40 away from those well plugs.
Any fuel, oil, WD40 or any other contaminant will keep the epoxy from adhering properly and sealing up the leaks. During our remanufacturing process, we boiled the bodies out in a caustic acid bath before gluing, so we didn't have any problems there.
Also, use steel epoxy or JBWeld. Regular epoxy tends to break down after a while from the heat. You will need to let the glue cure for 24 hours before use, unless you get the JBQuick. It is good to go in 3-4 hours.
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 38
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From: Flowery Branch GA
Sounds good... I took it apart and cleaned and blew everything out it looks good. the valve seat was simple the biggest headache was the throttle position sensor.. does this area get sealed or does gas not get into this area? For the most part it was straight forward... One good thing I did not have any extra parts left over. 
Thanks for all the help this C3 has been one learning experince. When I bought it the only thing it had going for it was new tires and a 3500 dollar paint job a everthing else Bubba had worked overtime and has lots of relatives.
Thanks loads
Steve
Thanks for all the help this C3 has been one learning experince. When I bought it the only thing it had going for it was new tires and a 3500 dollar paint job a everthing else Bubba had worked overtime and has lots of relatives.Thanks loads
Steve
That is quite an accomplishment. It should be a lot easier to work on now.
