So, I finally got around to trying to diagnose a coolant leak that has resulted in my '69 427 sitting dormant for far too long. The last time I drove it, a few minutes after I parked, my garage was awash in lovely green fluid. I got a cool morning today and decided to back it out to once again see if I could find the source (I couldn't see anything from the top side when it occurred many months ago). Well, believe it or not, I didn't get it to leak, which doesn't necessarily make me feel better, because problems like that don't just fix themselves.

Anyway, after I got the grouchy old girl fired up, no doubt mad at me for letting old gas sit that long (even with Stabil), I ended up with a couple fueling issues, one of which was an easy fix. Because I saw gas pooling on the manifold when I started it, I removed the air cleaner assembly to expose the carbs. The center seemed to be doing more or less ok given how long it sat, but even at limited RPM's I saw fuel pouring into the front carb (but not the rear). I checked the vacuum lines and they seemed properly fastened where they belong. But a fair amount of gas was making its way into that front carb when it shouldn't be.

I have a feeling the ultimate answer I am going to hear is I let the carbs sit too long, and I am looking at possible rebuilds. They were behaving just fine when I put it away and had my Vette shop go over everything not all that long ago -- well maybe 2 years at this point. I will also note fuel was somehow making its way on top of the front carb -- not sure how. But give me your best educated guesses at what I am looking at. And while you are at it, I wouldn't mind someone taking a stab at why, when I filled the coolant system with water to check for the leak, I got no leak. It may be relevant to know the engine was nice and hot from a fun cruise when the sizable leak occurred, but I did not allow the engine to get too hot today for fear of boiling the water a hurting the engine.

As always, thank you for your help. And please keep in mind, if the phrasing of my thread has not sufficiently exposed me, I am not exactly a great mechanic.

 

Float stuck DOWN allowing fuel to continue flowing into carb. You can try rapping the side of the bowl with the handle of a screwdriver to see if it will free up. Stabil is good for preserving fuel; but it's also good a gumming up carbs. If you can free it and get it running OK, more use may clear out the gunk.

If not, you will need to do a minor rebuild (remove, partially disassemble, clean, new gaskets and reassemble) on the end carbs...at least.

 

Thank you 7T1vette. I have a feeling this is a basic issue/solution, just one that does not occur to me, not having a ton of carb experience. I sent my Uncle a link to my question (he has owned period cars since they initially roamed the Earth), and he immediately called out not only the potential float sticking, but also the high tech solution of convincing it with the handle of a screwdriver.

It was kind of interesting showing/telling my 16 year old what I was seeing as I turned a few bolts to get access. I explained there was a (satisfying) time when you couldn't just plug your car into the diagnostic computer and have it give you answers. But then again, I couldn't help but appreciate the reliability and low maintenance needs of my modern daily driver, which would smoke this old high performance Vette. And, knock on wood, I honestly can't remember the last time I stood on the side of the road with a break down or a flat tire.

Anyway, thanks.

 

To be sure if your float is stuck or not, open up the side brass site screw on the float bowl in question. If fuel pours out the hole when you start the car at an alarming rate, your float is stuck down or your needle valve is stuck in the open position.
The needle valves are a cheap fix at almost any auto part store.
Dirty old fuel or rust sediment from the fuel tank may be your problem or just gummed up old fuel sitting in the carb.
The tripowers have no inline fuel filters unlike most other corvette models other than the strainer in the tank and the brass strainers on each carb.
Good luck, I have been in your same situation.
Pete