Monkeywrench

I've been smelling gas slightly latley but I assumed it was due to my rich running Qjet (next on the list to tune) Anyway when I go home from a spirited ride it was stronger than ever. I traced it down to leaking out the bottom of the vapor canister. I've heard they can split and leak alittle but I mean this can was more than 1/2 full of gas. Could my rich condition be pulling too much fuel through the carb and sending it back into the canister? Also I had fuled up before going for the ride. I did a search and found that filling the tank too high (I didn't think I went that full) could cause it to flood the canister.

Any thoughts?

rjs82vette

If you like to top off your tank it can drain into your canister... that and the fact that you are driving and the gas is surging back and forth can force more gas into the canister.... but this is the first time I have heard that it filled the canister up halfway..... I havent had a problem with the vet but I had a Dodge truck that did this....

Chris@VetteFinders

Whew, the tank must be pressurizing. The tube that goes to the canister is at the very top of the tank. Even if you fill the tank totally to the top, I doubt it would reach the tube. Perhaps the second fule line is plugged (return)?

John's Shark

I have a 71 that I am just beginning to learn about the vapor canister. I pulled mine from the car just last night. Mine is open at the bottom except for the filter. I don't see how mine could fill with gas at all since it's open at the bottom. Is your's a different design?

79MakoL82

I wouldn't think it would have anything to do with your rich condition, as the reason for the connection to the carb is to use the vaccum to suck the vapors in to the carb, is it not? So if your carb is creating vaccum, how could the fuel go against the direction of the vaccum. Is your vaccum hose to the carb OK?

Chris@VetteFinders

I think the vacuum would pull the fuel from the gastank to the canister because of the vacuum from the carb

Monkeywrench

Yes mine is fully enclosed. It appears to be "weeping" from the bottom. Possibly a crack in the housing. Regardless from the way I understand how it works it should "fill" will gas. It should only ever have a small amount in it. I didn't have time to check the hoses. Possibly one of them is not connected correctly or is leaking vacuum... I'll check tonight and let you guys know what I find.

Thanks for the info..

John's Shark

The canister on my 71 is definitely open at the bottom except for a filter. I don't see how it was designed to hold liquid gas. Maybe that is why you are smelling fumes. If liquid gas is backing up all the way to the canister, it will drain out the bottom. At least on mine. I have several pictures of mine if someone can post them on this thread you will see what I mean. Email me at moorej@bswllp.com and I will send them to you to post. I don't know how or I would do it myself.

John

John's Shark

Monkeywrench was kind enough to offer to post the pictures. Check back this weekend for pics. I will view from home but may not be able to respond. I have been having access problems from home.

Monkeywrench

Here are John's photos:









I don't think mine is open at the bottom. I'll have to take another look however...

Thanks for the photos John...


[Modified by Monkeywrench, 4:52 PM 2/22/2002]

TQ67

I have a 71 Roadster as well. For what it is worth, I always fill the gas tank right up to the bottom of the cylindrical neck and I've never noticed a leak, or smell, or filling of the vapor canister.

mrvette

OK, two things, I have a '72 convertible, so under the right conditions, I smell gas...and it's from that gasket on top of the filler leaking a bit when tank is full, and then maybe leaking hoses on the liquid/vapor separator...it's a 2" cube thing on top of the tank on driver's side...two hoses, one to the tank the other to the canister...there is a float ball inside, keeping liquie out of the canister, but allowing a MILD suction to the tank...this is supposed to happen only when engine is running, there are two tubes going to the engine...one is large and is set for suction ABOVE the throttle blades...the other smaller one is connected to manifold vac directly...and controlls a valve that opens only when engine is running, and puts fumes then from canister into the induction air...ABOVE the throttle blades....

now if the canister is full of gas, and you have a missing or leaking controll valve...mounted on top of the tank there....the canister CAN fill with gas...probably when the tank surges to drivers side when turning right....

that float is not supposed to let much if any gas past it, just fumes...

most of the gas smell I experience is in that gasket on the filler neck or a poor design gas cap with leaky gasket on that flat flange...I cure that last one with a 3/16 O ring on the filler neck for that spring section of the cap to seal against.....

the tank either is vented to atmosphere for temp/fumes/pressures differentials...or needs connected to a mild vacuum source to let engine burn the fumes...one way or the other....

GENE

Monkeywrench

Thanks for all of the responses. I've been concentrating on other thigs since the engine runs well so I never noticed the following. My headlights, wiper door, PB etc.. never worked right and I assumed I had some leaks in my vaccum system. So after this incident I checked it all out.

WHAT A MESS! I have one line running from the carb that splits to the PCV and the PB booster. THAT"S IT! No other vacuum anywhere!!! Some vacuum lines split and rejoin later to make a full circle. Others just end not connected to anything. Jeeze...:eek: I assume when Bubba dropped the 350 in place of the 454 he just got the minimum required to get it running. So I'm very quickly going to place an order for all full vacuum kit. Rip it all out and start from stratch.

So any reccomendations for one kit over another? I've checked out the major parts places and most run about $100... Any experience? :confused:


[Modified by Monkeywrench, 9:03 PM 2/24/2002]

Racer16k

The canister on my 73 leaked gas out the bottom until I replaced the check valve at the tank on the drivers side of the tank. Mounts on a bracket welded to the tank on my 73. Replaced the check valve, no more gas leak.

rjs82vette

I just got done doing all the vacuum hoses, t connector, check valves on my 82 and it cost me under $20.00... I just got the hoses and cut them myself... I also could cut them to the length I needed to run them so they looked perty... All the kits that I found were only for the lights and wiper door.... not for the engine or heater/ac controls....

Monkeywrench

I thought about going that way but I'm missing a lot of the t-connectors and check valves etc, so by the time I bought all of that I basically could get the hoses for free (and color coded). Zip and Corvette Central sell kits for the "entire" vacuum system...

TQ67

I had remendous success with a kit from Dr Rebuild. ZIP was sued and lost a lot of money for copying Dr. Rebuids products. Make sure to purchase the Vacuum line trouble shooting guide. It will save you MANY HOURS!!!