Mixture control solenoid adjusting screw plug

[Clone TIE Pilot]

I am looking for a source for a replacement plug that goes in the airhorn over the lean stop adjusting screw for the mixture control solenoid. A previous rebuilder left the plug out as its commonly suggested to leave it out for easier readjustments. However, one of the purposes of this plug is to lock the adjustment so the lean stop can't migrate out of adjustment which is an issue I am having. I detected that without the plug, my lean stop adjusting screw vibrates upward and limiting plunger travel, thus making the mixture rich and screwing up the dwell. Moreover, I am having an issues finding a source for replacement plugs, Quadrajetparts.com had them but they are currently shut down and who knows when or even if they will reopen. Anyone else know sources of oddball E4ME parts? Worse comes to worse I can try extracting a used plug out of one of my spare parts Qjets.

One more note is that my current carb has a old lean stop repair kit installed. This repair kit replaces a stripped out adjusting screw with a special stud and nut. It seems stronger but looser than a stock screw, the nut turns easier than the stock adjusting screw so it might migrate worse than a stock screw and has a greater need for locking.

 

[69hurstolds]

I was just thinking about this very thing today. I have an NOS carb I want to use on the 84 H/O and I'm going to go ahead and remove the plugs on the new carb. In the likely event I'm going to have to monkey with it, I'm doing it as a pre-emptive strike. But I want to put the plugs back if I can. I can probably drive out the rich stop and lean stop and maybe re-use them if I don't screw them up, but the TPS plug will be sacrificed because that's all you can do. I'm not wanting to RTV over the hole, but I will if I have to.

They come in the Delco E-jet carb kits along with some of the better aftermarket carb kits, and the TPS plug comes with the Delco TPS packages, but who wants to buy a bunch of carb or TPS kits just to get those plugs? Not only do they keep the adjuster locked when installed correctly,it keeps dirt out. It wouldn't be as bad if the adjustment hole was inside the air cleaner area (filtered air), like the rich stop, but it's still undesirable.

They're not serviced separately. If GM had part numbers for them, I'd sure as heck have the numbers already.

Snooping up under some rocks, I did find this, however. Not sure 12 and change is worth it. Might be, but hmmmm.

1984-1990 305'' 307'' Electronic Quadrajet carburetor plug and seal kit CCC E4MC | eBay

BUICK E4MC: 1984-1990 307" 5.0L A/T. CADILLAC E4MC: 1986-1990 307" 5.0L A/T. CHEVROLET E4MC: 1986-1990 307",307" 5.0L A/T. PONTIAC E4MC:1986-1990 307", 5.0L A/T. Electronic Rochester Quadrajet carburetor.

www.ebay.com

Hopefully quadrajetparts.com will open back up.

 

[Clone TIE Pilot]

I was just thinking about this very thing today. I have an NOS carb I want to use on the 84 H/O and I'm going to go ahead and remove the plugs on the new carb. In the likely event I'm going to have to monkey with it, I'm doing it as a pre-emptive strike. But I want to put the plugs back if I can. I can probably drive out the rich stop and lean stop and maybe re-use them if I don't screw them up, but the TPS plug will be sacrificed because that's all you can do. I'm not wanting to RTV over the hole, but I will if I have to.

They come in the Delco E-jet carb kits along with some of the better aftermarket carb kits, and the TPS plug comes with the Delco TPS packages, but who wants to buy a bunch of carb or TPS kits just to get those plugs? Not only do they keep the adjuster locked when installed correctly,it keeps dirt out. It wouldn't be as bad if the adjustment hole was inside the air cleaner area (filtered air), like the rich stop, but it's still undesirable.

They're not serviced separately. If GM had part numbers for them, I'd sure as heck have the numbers already.

Snooping up under some rocks, I did find this, however. Not sure 12 and change is worth it. Might be, but hmmmm.

1984-1990 305'' 307'' Electronic Quadrajet carburetor plug and seal kit CCC E4MC | eBay

BUICK E4MC: 1984-1990 307" 5.0L A/T. CADILLAC E4MC: 1986-1990 307" 5.0L A/T. CHEVROLET E4MC: 1986-1990 307",307" 5.0L A/T. PONTIAC E4MC:1986-1990 307", 5.0L A/T. Electronic Rochester Quadrajet carburetor.

www.ebay.com

Hopefully quadrajetparts.com will open back up.

Looks like that kit is the best I am going to do. Even on Quadrajetparts just the plugs are $2 plus shipping.

Besides locking the lean screw so it doesn't walk out of adjustment the plug also seals the fuel bowl to prevent entry of unfiltered air as you said. A missing plug might even act as an vacuum leak through the EVAP. Not sure if the access hole in the airhorn could just be tapped for a setscrew? That would at least require removing the airhorn which I don't want to do again at this time.