Sometimes my carb leaks sometimes it doesn't?

14platoon

1970 type 2 1800cc engine with dual factory carbs.
Sometimes my carb will be leaking fuel, this appears to come from the base gaskets but I can't be sure. I replaced the gaskets recently.
I have found the carb to be leaking on occasions, however when I dry it and observe I can see no leaks. Other times it does not leak at all? When it's leaking there are drips from the base gaskets onto the metal tin work.
I can't work out why it doesn't leak all the time,any ideas please.

busdaddy · Posted: Wed Feb 11, 2015 8:05 am Post subject:

Ever had the throttle bodies rebushed?
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14platoon · Posted: Wed Feb 11, 2015 9:36 am Post subject:

No...could it be the linkage leaking then? Still not sure why it only does it rarely but not on most occasions?

busdaddy · Posted: Wed Feb 11, 2015 9:44 am Post subject:

99% of the time gas coming from the base of the carb after shut down or when pumping the throttle not running is a sign of loose throttle shaft bushings, having them rebushed will make a big difference in how it idles.

The next question is where is the gas coming from if you are not pumping the throttle?, your float levels may be set too high, or your needles and seats are getting weak, or your floats are sinking, or a combination of those. Or modern fuel is messing with your vintage bus, here's some recent discussion on that subject: http://www.thesamba.com/vw/forum/viewtopic.php?t=618963
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14platoon · Posted: Thu Feb 12, 2015 12:29 pm Post subject:

If the float was sinking would this happen every time?

busdaddy · Posted: Thu Feb 12, 2015 4:29 pm Post subject:

14platoon · Posted: Sat Feb 21, 2015 8:53 pm Post subject:

I'll check the float when I get a mo.

14platoon · Posted: Fri Feb 27, 2015 9:08 am Post subject:

I took the carb off. When I tilt the carb slightly, fuel comes out of the base and had obviously been leaking past the gasket. Should fuel leak out the bottom when at an angle? Obviously it shouldn't leak past the gasket but should fuel be moving out the base at all, is there not a shut off to stop it?

busdaddy · Posted: Fri Feb 27, 2015 10:06 am Post subject:

14platoon · Posted: Fri Feb 27, 2015 1:36 pm Post subject:

Ok that makes sense. I have a rebuild kit on order, will that sort my issues out or do I need to adjust float levels etc? I appreciate you can't tell by looking so how do I know if the float levels are too high?

Second thoughts, if my fuel has recently started leaking then I'm guessing the cause is some sort of wear as bus daddy has suggested otherwise the fuel would have been leaking all the time. I'm therefore guessing float levels are probably good and maybe the seals or the actual float is leaking, again as bus daddy has stated.

14platoon · Posted: Tue Mar 03, 2015 11:21 am Post subject:

I don't want to remove the jets as I paid for a tune up a few weeks ago. Is there a way I can clean the body and integral parts without blocking jets etc?

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52739

You need to read the explanations of how the carbs work and the rebuild instructions in both the Bentley and John Muir's Idiot Book. Only after educating yourself should you try and do a rebuild. Doing a simple rebuild shouldn't much affect the rest of the tune up and if it does then the tuneup needs to be redone anyway. Also it would be good to have a scale available to weight the floats.

14platoon · Posted: Wed Mar 04, 2015 1:42 pm Post subject:

No worries, I have both the books out and ready. Just wondered if there was a way to clean, I have blasted the innards and jets with carb cleaner now. The fuel bowl had a very thick layer of crud and would undoubtedly have messed with the levels. I will check the fuel level when I'm complete.

14platoon · Posted: Fri Mar 06, 2015 2:18 pm Post subject:

Just completing the job. I can't find the mark on the auto choke cap but not on the main body of the carb, anyone know where I can find it or do I just guess?

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52739

14platoon · Posted: Fri Mar 06, 2015 4:28 pm Post subject:

Any ideas where to start with the choke alignment?

busdaddy · Posted: Fri Mar 06, 2015 5:16 pm Post subject:

Turn it until the choke plate just closes loosely, or if you are doing this indoors at room temp leave it open a crack.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

14platoon · Posted: Sat Mar 07, 2015 5:52 am Post subject:

Thanks, ready to go back on now. All gaskets replaced, float level checked, needle valve replaced.....fingers crossed!

14platoon · Posted: Sat Mar 07, 2015 9:20 am Post subject:

When I took the carb off, it would leak through the bottom of the throat. Since replacing the needle valve gaskets diaphragms etc, it doesn't appear to be doing this anymore.
Carb back on, runs great and no leaks spotted......yet.

14platoon · Posted: Sun Mar 08, 2015 8:10 am Post subject:

Checked the bus this morning, no leaks whatsoever. Job done!


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Sometimes my carb leaks sometimes it doesn't?
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