C3 68 Tri Carb leak

[Rich G.]

The rear carb on my 68 L71 is leaking a serious amount of gas. It looks like it's coming from the fuel line fitting (which is tight) but it could be coming from more toward the center. The fuel line doesn't look like it's going "straight" into the carb, either. Is it likely a bad flare fitting, or are these carbs noted for leaking elsewhere?

This car is new to me, so, let the learning begin.

Thanks

Rich Giannotti

[Joe L.]

Re: C3 68 Tri Carb leak

Rich-----

It's hard to say, for sure, without actually seeing the car. However, I would say that there are, at least, 3 possibilities:

1) the compression fitting flair may be damaged on the fuel line. This flair must be PERFECT in order to seal properly. It must also be a perfectly formed DOUBLE flair;

2) the tubing seat in the carb-mounted, steel fitting may be damaged. Once again, this seat must be PERFECT for a seal to occur;

3) the threads in the carb float bowl into which the steel fitting threads may be damaged or erroded. If so, the fuel will be leaking from the interface between the fitting and the float bowl. This is often hard to detect, though, unless one is very carefull. To do so, wipe off the fuel carefully and completely. Then, very carefully, observe where the fuel leak originates from----the interface between the tubing nut and the steel fitting OR the interface between the steel fitting and the float bowl.

[Clem Z.]

Re: C3 68 Tri Carb leak

if the leak is at the interface of the fuel line nut where it enters the fuel filter fitting on the carb i have used teflon tape,not to seal the leak but to allow you to put more torque on the fitting so the flare will seat. the teflon tape acts as a lubricant for the fitting threads and allows you to tighen them up tighter. what you also can do if the fuel lines are new is to take a fuel filter fittings off of the carb and pre tighten them into the fuel line on your work bench so you can prefit the flare where you can get to them easier and then reinstall them on the carbs. industrial supply places sell copper washers for flare fittings which will solve your problem because the copper is softer than either the steel fuel filter fitting and the steel gas line. i have used these often to get a good seal on leaking fuel lines fitting flares

[Terry M.]

Re: C3 68 Tri Carb leak

If the leak is between the float bowl and the fuel filter nut, IIRC there is a gasket at this location. Be sure the gasket is installed correctly and is in good shape. I think it is a thin metal gasket. Hope I am not mixing up Holley and Rochester carbs in my old age.

[Rich G.]

Re: C3 68 Tri Carb leak

Joe, Clem, Terry

I think it's comming from the interface between the float bowl and fitting (Joe's choice #3). I'll have a better look tomorrow in the day light.

Thanks for the tips on possible fixes too. I'll let you know what we find. This carb had been recently replaced by the former owner, sooooo, anything goes.

Rich Giannotti

[Clem Z.]

Re: C3 68 Tri Carb leak

sometimes using 2 of the rubber covered metal gasket there will help. holley also has a better nylon gasket part # 26-102 but the will not pass as orignal

[Rich G.]

Re: C3 68 Tri Carb leak UPDATE

Well, a thorough tightening of the inlet to the rear carb stopped that leak. Also the 4 screws on the front cover were a little loose. Once that river of fuel was stemmed, it was evident that the center carb was leaking around the base. So it has been pulled of and disappeared into the darkness with my friend Bill, who knows about these things. He thinks the accelerator pump diaphram may be a problem. In any case, he's been there before, so I can go back to worrying about cleaning the car, which is what I do best.

Thanks for all the advice

Rich Giannotti