Hi all
My qjet appears to have cracks that are seeping fuel into the manifold.



Am looking for a decent replacement. It's a R4-4MV for a 73 BBC. It has the divorced choke.I can't see the sense in going to Holley as I would have to forgo my original air cleaner.
The old one had a slightly stripped intake and I was able to fix that but the crack says I would need to dodgy it up with epoxy and I just don't want to go down that path.
I've seen carbs unlimited and zip has the right beast but not in stock.
Any thoughts on where to go for a good unit?? I'm in Oz so would have to buy sight unseen...problem
Tia

 

I have a 7044213 that I used for parts and right now it is headed for the dump. If the base plate is where the cracks are I will send it to you for the cost of shipping. If you want the entire carb, I would be willing to send that also, but it has been stripped of most of the parts, but the parts from you current carb would work.

I can send photos if you want.


Gene Ventura

 

Thanks Gene
It seems to be one of the two little nipple looking affairs that are part of the float bowl. Not sure if yours would be the same as mine. Give me a mo to look it up.

 

I don't see any cracks. Where are the cracks? The only cracks that can seep fuel are cracks in the float bowl - the photo shows the throttle plate. The throttle plate is not a fuel-retaining part of the carb. Are you sure you need a carb..? Any commercially-rebuilt carb you buy will be junk. E-mail me for my paper on commercially built carbs.

Lars
V8FastCars@msn.com

 

You are experiencing a very common Q-jet problem. It can be repaired. This website has some good info. http://www.cliffshighperformance.com

My carb had the same problem and I sent it to him for repair and the repair worked vey well. If you have the desire he also sells a book which shows you how to repair the the leaks in those two plugs and also the the well plugs under the base plate. Those are also certainly leaking as well

Gene

 

If you're referring to the primary well plugs as Gene indicates above, you can easily repair those yourself.

First, verify that they're actually leaking: Set the carb up on some tall sockets on your workbench, fill the bowl with fuel, and observe that the fuel is actually coming from the plugs. Since the plugs are the lowest part of the bowl casting, fuel coming from another leak path will eventually drip off the well plug castings.

If the plugs are actually leaking/dripping, pull the throttle plate off the carb. Drill out the plugs and then drill/tap the plug locations for a 10-32 thread. Note that they're at an angle, and you want to duplicate and maintain the angle of the existing bore.

Once drilled and tapped, install 10-32 x 1/4" long flat head socket cap screws into the tapped holes. Coat the screw threads with JBWeld epoxy (or similar structural epoxy) before installation and snug them into the holes.

This produces a permanent repair that will not leak. Many people will simply coat the plugs with epoxy, but this is a temporary fix that will quickly start leaking again. If you do the drill/tap/screw fix, the bowl will never leak again.

You're much better off doing this than buying a piece-O-crap "rebuilt" carb.

You can also e-mail me for my Q-Jet setup paper. This paper contains the instructions for the repair as noted above, and has some other notes about bowl leaks as well.

Lars

 

Thanks Lars
Will buy a gasket kit after testing and have at it. No doubt you've saved me a bomb.
Appreciate it.

 

So..after much research I have sent an email to cliff ruggles and ordered his book on qjets.
I tested the float bowl as Lars advised (ta mate) and stuff me it didn't drip one bit. Fuel is coming from else where. There is a carbon build up in the inlet manifold directly below the carb, but is clean otherwise. The throttle body gasket is cooked around the primary well plug area. I am not going to reinstall the heat shield as hopefully this leak affair will be fixed.
Will await more advice and order parts to suit.
Let this be a lesson to all other newbies. One job at a time.

 

Ok. Another day and night of reading. For anyone with an IQ above 0 minus 50 I would have to say that Lars papers on Qjet tuning are a must. I jumped in at 1am and stripped that puppy down with great expectations. Expectation fulfilled. In a bad way! The air horn was warped to the point where it was hard to find a flat reference point. The float bowl has one corner that is a full 1/4" shorter than the rest of the unit eg, bubba had a mushy flashback and took to it with a hammer. The power piston bush was stuffed. But thats ok coz the top of the power piston tube was munted as someone had taken to it with a screwdriver and hammer (check piccy) Funnily enough, the pump, float and bowl, primaries and secondaries all in new condition. Float was hung thru the hole on the float tho! The gasket was torn around the power piston and rods. Idle pick-up tubes were floating around un attached.
I thought she was running a bit rich!!
As a tradesman (not mechanical) I am sorely miffed that there are people out there that would go to so much trouble to knowingly stuff something up and pass it off to an unsuspecting public.
As a true masochist, I have ordered a rebuilt beast to keep me going until I can find that elusive "right" carby. I have no wish to change to a holley or any thing else for that matter.
I'm going to keep this thread going in the hope that other newbies might read it and develop an insight into choosing the right gear thru inspection and good old information passed from one to another.

 

If you've ordered a "rebuilt" carb, you might also want to send me an e-mail request for my "Commercially Rebuilt Q-Jet Problems" so you can be prepared for the junk you're going to get...

Lars
V8FastCars@msn.com