I hope i'm in the right section...

Does anyone know much about the Carter BBS carburetor? I’ve just rebuilt mine - I did reset the float but I’m a machinist and very good at measuring. It runs great, idols great, MPG hasn’t suffered... but every time that I kill the engine it smells like gas is leaking.

It’s not leaking. It just smells like it. If it’s leaking I can’t find it. The top carb gasket is damp/shiny. Sometimes there is a very small amount of wetness around the accelerator pump shaft. You couldn’t drop gas on it small enough to make it look the same — it’s small. It could be dumping it down the intake - that was the original problem - but I don’t know if it would smell this much. I have a 40 X 50 shop and it stinks of gas instantly and forever.

It’s not that hard to re-adjust the float but I want to make sure before I take it apart again.

Danny

Check your fuel pump.......

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

The fuel pump is new... comparitively. I've put 200 miles on this truck in the last 8 years - I've fiddled with the points three times, set the timing, and rebuilt the carb twice.

I replaced the fuel pump, I think, before all of that. It filled the crankcase up with gas and hasn't done it since. Of course it doesn't have the purty glass settling bowl on it but it's new.

Thanks
Danny

Yep what he said ,,,take a good look at the fuel pump. In the last year we had 2 cars do the same thing, my 67 and my 63 just this week. Kept smelling gas after shut down and on the 67 while driving. Shut it off open the hood and everything was dry. but still a strong smell. Eventually the leak and smell got worse that you could see it when running. Just a thought but not to be over looked. Had me scratching my head the first time. The second time I swapped out the pump as soon as the smell showed up and the problem was solved.

Replacing the fuel pump likely won't get you anywhere — it's doing what it's supposed to do, generating pressure in the line from the pump to the carb. The claim was made in '73 that newly that year, slant-6 fuel pumps had an inbuilt bleed-down path to relieve line pressure after engine shutdown, but I've never seen a slant-6 pump (factory or aftermarket) that actually had any such a function. Then again, the same "What's new for '73" engineering bulletin also claimed the newly-redesigned slant-6 fuel pump also had a screw-in fuel filter in the outlet tower. Haven't seen one of those, either. Guess neither change made it past the bean counters. The internal bleed-down might've been a good idea, had they implemented it, but they found other ways to achieve the same result.

There was a TSB and "Flood-Stop" kit released in '68 to alleviate an overpressure condition in the line from the pump to the carb after engine shutdown. It consisted of two brass fittings. One threaded into the fuel pump outlet ahead of the pump-to-carb line, and the other spliced into the flexible hose between the frame line and the fuel pump inlet. Each of these fittings had a tiny pinhole at the end of a small hose nipple off the side of the fitting body. A short length of hose connected the two pinholed nipples. This provided a very low volume controlled "leak" from the pressure to the suction side of the pump. Not nearly enough ever to starve the engine for fuel, but enough so that when the engine was shut down the excess pressure in the pump-to-carb line would be bled off. Later, the 3-nipple fuel filter (5/16" inlet and outlet and a 1/4" vapour return nipple) was introduced for much the same purpose, but the return line was run all the way back to the tank. The flood-stop kit is long since NLA, but the 3-nipple filter is readily available. You can install one if it becomes necessary, but you'll have to figure out how to plumb the return line. Not too difficult, just a hassle.

As a first step, do the fuel line mod to minimise heat transfer to the fuel between the pump and the carb, and make sure you have the correct base gasket between the carb and the manifold. It should be 5/16" to 3/8" thick, not the 1/8" thin one. Also make sure your "heat riser" (manifold heat control valve) is working correctly. And yes, you do need to make sure the carb float and carb bowl vent plate are set correctly.

But, having said all that, it sounds like your setup's behaviour might not be too abnormal. Remember, the pre-'70 (California) pre-'71 (49-state/Canada) vehicles had the carburetor vented directly to the atmosphere, so yeah, when you park the vehicle with a hot engine, you're going to smell gasoline...especially with today's more odiferous gasoline/alcohol blends. If you're getting evidence of liquid gasoline running up overtop of the carb via the accelerator pump hole/bowl vent and dripping down onto the manifold below, then yeah, you definitely need to do some work to correct it. The "sounds like something dripping/leaking" effect, if you don't see any such external liquid fuel dripping, is usually fuel dripping from the nozzles inside the carb and hitting the hot throttle plate/manifold. Remove the air cleaner and take a look.

If you want to solve the problem "all the way solved" so you don't smell fuel, you can install a '70+ (California) '71+ (49-state/Canada) carburetor and put together a fuel vapour canister system as was done on '72-up models. It's not too difficult. Or you could park the truck outside!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

You've got PM........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Just to get you started, the 3-nipple fuel filters have a 0.060" orifice ahead of the vapour return, and as I say, the flood-stop kit's orifices were truly pinholes. Really tiny.
I'm assuming "closed" = "heat on" (fully clockwise as viewed from the front of the engine) and "open" = "heat off" (fully counterclockwise as viewed from the front)...right?
H'mmm. What kind of carb kit did you buy? Every one I've ever bought has contained the same illustration-and-instruction sheet printed up by the Techlit company...and has an illustration of the vent plate and its clip. The clip is a sort of safety pin looking wire dingus that clips onto the accelerator pump stem in any of three positions (low, medium, high) according to which notch in the stem the clip is snapped onto. The top of the clip lifts the round bowl vent plate up as the accelerator pump stem ascends so the bowl vent is open at idle, and lowers the bowl vent plate onto the carb surface as the pump stem descends so the bowl vent is closed off idle. A missing vent plate will cause poor fuel mileage and excessive gasoline smell, while a vent plate that never opens 'cause the clip's missing will cause overly-rich starting and idling problems.

There are also pictures in the factory service manual. If you haven't got the factory service manual, you definitely need it.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Nope.
In this illustration, the plate is #23, the clip (shown here as a simple jesus-clip, rather than the more robust type I previously described) is #27, and you're probably not quite making the connection as to how this all goes together because the top casting in this particular illustration is a '71-up (or California '70-up) ducted type, not the earlier type you're working with. You, uh, didn't answer my question about whether or not you have the necessary factory service manual.
That's the right idea, if that's the type of clip you've got to work with (rather than the "bent safety pin" type I previously described). The correct position of the clip in the upper, middle, or lower notch in the accelerator pump stem is dependent on the position of the throttle lever-to-accelerator pump lift arm link. If the link is in the outermost hole of the throttle lever, then you use the lower notch. If the link is in the innermost hole of the throttle lever, you use the upper notch. If the link is in the centre hole, you use the centre notch. Then you use two pairs of pliers on the lower "elbow" bend in the link to set the bowl vent opening according to the specification, at which point both the bowl vent and the accelerator pump travel will be correct. Yours is not presently adjusted correctly, for we can see the bowl vent plate is not lifted off the carburetor when the throttle is closed, and it should be so lifted. We can also see you've got the thin carb base gasket in place instead of the thick one.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.