Unanswered questions about Q-jet well plugs

[crypkilla]

My carb appears to be original to its application. 78 Chevy 1 ton pickup
Carb #17058229

Problem #1) I drilled into the primary plugs with a 1/8 drill bit. I then sort of broke the heads off the plugs, but the rest of the plug remains in the well with a 1/8 inch hole in them. I keep chipping away at them with a little pick but they don't wanna come out.

Problem #2) Since the plugs are so soft I thought I would just run the tap anyway and it would clear out the remaining plug material and tap the casting. I used a standard 10/32 tap. It says 10NF32 right on the side of it. I thought this was the correct size for the primary wells, but all the tap did was put threads into the remaining plug material. And the threads arent perfect becuz I gouged parts of the remaining plug material with the pick. It the remaining plug material was removed, I feel that the tap would be too small to put threads into the casting.

Any help? I don't wanna mess this up.

[omaha]

I think a 10-32 tap uses a 5/32 drill bit. find a scrap of aluminum and try drilling a 5/32 hole and then try out your tap to see if it will work. also a number 21 drill bit should work.

[crypkilla]

Perhaps i wasn't clear. My 10/32 tap tapped my 1/8 inch hole just fine. But both are too small for the primary wells. The tap did not put any threads into the casting of the carb. The only threads it made were in the soft plug material that remained in the well becuz i have yet to get it all out.

Cliff says here http://cliffshighperformance.dreamhosters.com/simplemachinesforum/index.php?PHPSESSID=8ivqderih6r1ihl274hklj2cv1&topic=1503.msg7223#msg7223 that the small wells are tapped with a 10/32 but this does not seem correct for my application.

What am I missing?

[crypkilla]

I've discovered my mistake. The aluminum casting of the carb is a dull gray. But when you scratch it it's bright shiny silver. After drilling the plugs (which are of course very soft, and a different color from the casting) and knocking the heads off there may still have been a small amount of plug material around, particularly on the recess where the head of the plug seats. I scraped around with a sharp tool and scratched the aluminum casting on the inside of the well which is itself also very soft. I then mistook the soft shiny aluminum casting on the inside of the well for leftover plug material. I scratched at it some more and easily left a decent gouge. Before doing too much damage, just went ahead and tapped the hole, but my threads have a deep gouge in one area (just waiting to leak fuel).

So now I'm afraid my repair will be prone to leaking. I do not know if epoxy will seal this gouge in my threads or if i should retap the hole bigger. Also I was considering using JB-weld on the threads since I have some and admittedly have not purchased Cliff's repait kit. (As a starving college student, I have yet to scratch together the cash I need for a replacement choke pulloff and a rebuild kit) But perhaps it is important to use Marine-Tex...

[Cliff Ruggles]

JB Weld is useless for what  you are trying to do, it will soften up like bubble gum in contact with fuel and leak.

The primary plugs are easy to drill out as they are much softer than the casting material.  I use a bit around .150", and very carefully drill them not pushing really hard to drive any material ahead of the bit up into the casting.

The 10-32 tapered tap gets apprx 4 turns, this leaves a tapered seat for the plugs much like NPT threads.

With Marine Tex applied to the plugs, and tightening them into the casting, it will be a permanent repair.....Cliff