Leaking 30 PICT-1 Carburetor Pin

[PWS]

After overhauling my 30 PICT-1 carburetor I'm getting gas seeping out of the little brass pin situated on the passenger side of the carburetor. It seems to be tapped in gently but securely. Ideally, one would buy a replacement pin, but I don't know that they are available. I suppose one could epoxy this in although that may create future problems when it would need to be removed. This seepage occurs as the car just sits. I'm afraid to actually drive it until this issue is resolved. Any help or advice would be greatly appreciated. Thanks!

[Eric&Barb]

Can you post an image of the pin in question?

Have you tried to tap it in a little bit farther?
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[61SNRF]

The accelerator pump outlet check ball is held captive by a brass pin in the right side of the carb. This is a 30 PICT 2 but has the same circuitry. Look at #16 and follow the channel down the right where you see the pin and check ball.

If you thought the pin was the problem, ideally you would get one from Solex and not something generic.

Must say though I've never seen a carb leak from one. In theory the only time it should have fuel in the passage is when you're accellerating. If it were just a loose fit, I'd suggest remove and apply a dab of blue or red Loctite.

Why it leaks worse when sitting needs to be checked further. You say you've rebuilt the carb? Did you change the needle and seat?
Too high a float level or too high fuel pressure can cause fuel dripping into carb after shut down.
Take the air cleaner off after shut down and look down the carb with a flash light, you shouldn't see any excessive wetness or continual dripping.
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-Bruce

An ounce of prevention is worth a pound of cure.

[glutamodo]

I've never seen one of those check ball retainer pins leak before. Since I have a box o'carbs and another divided parts box full of misc carb parts I'd probably try to dig up a different one first. If it wasn't wanting to fit tight I might try taking a center punch and hammer and giving a few taps around the opening or in/around from the sides of that boss. I'm not sure if Loctite would hold up to fuel, I might try it though... last resort would be fuel resistant epoxy and I'd be vary sparing with it.

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Andy T.


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[PWS]

I have left the pin in place for now. However, I notice that in the photo by glutamodo, the pins are beveled. I don't recall mine looking like that. It never leaked before I did the overhaul. Perhaps in extracting it I have loosened things up slightly. I ran the car at idle today for about ten minutes and didn't notice any seeping during that time. But after the car has sat for a while I begin to see it. I did take off the air cleaner, as suggested, and took a peek down past the choke butterfly to the throttle but didn't see any excessive wetness. Carburetor is Bocar, which apparently is not the same as Solex. Still confused about this!

[61SNRF]

Bocar is generic south American OE but not German Solex, I personally have zero hands on experience with them.

In any case...How wet does it get?

Stage 1-Sweating and varnish forming around the fitting.

Stage 2-Heavy sweating with imminent drips forming.

Stage 3-Wet with active drips.

Better yet, a picture tells 1000 words
_________________
-Bruce

An ounce of prevention is worth a pound of cure.

[glutamodo]

slight correction:

Brosol is from Brazil.

Bocar is from Mexico.
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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[PWS]

With respect to post by 61SNRF, wetness is Stage 1 and never develops beyond that. There's just a very slow, spreading dampness. I examined this again this afternoon--very, very carefully this time. The wetness does not seem to be coming from the pin hole itself. Instead, it seems to be coming from around the base of the "boss"--not sure if this is the name for it--the little teat into which the pin is inserted. By "the base of the boss" I mean where the boss meets the carburetor body. If this is really the case, is it "new carburetor" time? I don't see any visible signs of a crack or fissure.

61SNRF says there should not be fuel in this passageway unless I'm accelerating. Well, the car has sat for 24 hours, and the wetness persists. When I overhauled the carburetor I did replace the needle seat & gasket, as directed--using the proper 1.0 mm (.040") gasket. I'm thinking--what next? Should I take off the upper part of the carburetor, look at fuel level in bowl, recheck proper gasket on needle seat? Not sure what else I can do.

[glutamodo]

It's not some hollow air passenge when there's no accelerator pump action going on. You want fuel out the accelerator pump right away when you move the throttle arm and if it was full of air, you would not get it. Yes, it's not under any pressure, but it's there. Heck, some carb diagrams show suction-induced flow through there at high engine RPMs. So there should be fuel in there pretty much at all times.

I've never been a fan of Bocar 34PICT-3 carburetors. (I do like the 30PICT-1 clones they used to make many years ago). But I've never seen any kind of damage to the passenges for the accelerator pump... beyond it getting full of varnish or other deposits, but never a crack.
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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[Blue69Baja]

[61SNRF]

I said "in theory" there is only fuel in the passage when accelerating, and I still tend to stand by that. My thinking is due to venturi vacuum, even at idle, most liquid fuel above the check ball should be drawn into the airstream.
However, it may not be true at all. With only the tiny calibrated opening exposed to the vacuum, and no venting on it's other end, the passage may indeed hold a small volume.

Continuing the theory, and I think all will agree, below the check ball there should a ready column of liquid fuel just waiting for the pump diaphram to act.

Regardless of where and when, there shouldn't be any sweating around the boss. If there are no signs of past impact or damage to the area, I would suspect a porous casting.
I have dealt with both oil and coolant leaks from porous castings in pressure cast aluminium engine blocks, so it is conceivable.

Kent Moore makes an aerosol leak trace powder that is very helpful in isolating such leaks, but at home you can also just clean the area and dust with simple talcum powder of any sort. With careful application and observation you can narrow it down to the exact source.
_________________
-Bruce

An ounce of prevention is worth a pound of cure.