Topic: carbs leaking gas after rebuild

[Jimsun]

Hey guys, after i rebuilt the carbs, I poured gas and all of a sudden, gas leaked from all the tubes. Any ideas? I've read some of the threads and i've measured them to spec height.

[LesterPiglet]

Did they leak before?

[Jimsun]

Did they leak before?

They did not all leak before. It was only carb 3 that was leaking (a few drops) now it's like a river.

[greenjeans]

How did you clean them ?    I've seen the overflow tubes split if they are boiled or cleaned too aggressively.

Other than that, it would have to be the float jets.  Sometimes when they are clean, they don't seal like they used too - the gunk and
varnish that builds up seals pretty good sometimes 

Check your float needles again to make sure that the spring/plunger still works smoothly. 

[flybox1]

if this is the first time you've filled them since being dry, just bang on the carb rack with a rubber mallet.  the floats are probably stuck.
if they do not shut off fuel flow, its time to revisit a clean tank, clean fuel, good seating float valves, and properly set float heights.

[luap]

 sounds like you forgot to put the float needle back in before you put the floats back on

[tlbranth]

sounds like you forgot to put the float needle back in before you put the floats back on

Now that's just plain cruel Lu.

[Ace]

Check that there isn't something like a hair in the needle and seat preventing it from closing. Push the needle closed with your finger, turn the gas on and see if it leaks. If it leaks then it's not seating/sealing properly. If it doesn't leak, then check float height and brass tube for hairline cracks which was mentioned previously. One thing that may have been overlooked is the drain plug screw and o-ring, I'd check that if all else fails.

Float height caused me issues on the last set I rebuilt.

[martin_uk]

I had the same problem after fitting replacement non OE float valves/seats.

Fitted the original ones and now fine. 

[jonda500]

my carbs were rebuilt by harisuluv, whenever I hook them up to fuel after they have been dry for some time fuel pisses out every where (except the overflow tubes!!?) but after ten minutes or so they come good and I can leave the fuel tap in the on position all day with no sign of a leak! My theory is that my float hinge pins are so tight that the floats wont move at first but after a few minutes fuel seeps in and lubricates the float hinges. (Oh and yes I realise that I need to check my drain tubes for blockages)

[Jimsun]

Thank you guys,. I will report back after I've inspected and replaced the float needle. Maybe it's the culprit?

Carbs 1,2 and 4 are fine, Carb 3 is still not good. Maybe the float needle wasn't as spongy. I never really kept at eye on this. Just the float height.

[tlbranth]

Typical culprits: Hole in float, dirt on needle valve/seat, float hitting posts or side of bowl, dimple in float tang.

[fendersrule]

Hard to believe that I haven't read this yet but:

Make sure to check the bowl casings for cracks from over tightening the valve screw. I found a cracked casing on one of my bowls.

[Jimsun]

Ive found out that carb 3 float needle needed replacement. I updated my carb question threadregarding a kit i want to buy. Link below.

The leak is coming from the over flow tube. Meaning the tube at the very bottom of the bowl (?). I have hoses connected to it

http://bit.ly/1l40wHT


Link to my carb question
http://forums.sohc4.net/index.php?topic=132617.0

[flybox1]

dont worry, thats where they are supposed to leak so gas doesnt flow onto a hot engine.

do you need the whole kit, or just float valves?  you said you rebuilt the carbs in your first post 

[fendersrule]

Aftermarket carb kits are only good for gaskets (sometimes) and various other minor parts. Usually cleaning up the Honda stuff will yield much better results rather than using carb kit items. For float valves, we don't have a choice.

How did you verify that it was the float valve? A cracked casing will still cause gas to leak out the overflow tube.

Did you remove the bowl and fill it up with water to see if it leaks out the overflow? I'd like to know how you've verified things.

[bjatwood]

Could be a crack in the brass standpipe also. These pipes have been known to leak because of these hairline cracks. Something to look for/at when redoing these carbs.

[Bankerdanny]

Aftermarket carb kits are only good for gaskets (sometimes) and various other minor parts. Usually cleaning up the Honda stuff will yield much better results rather than using carb kit items. For float valves, we don't have a choice.

How did you verify that it was the float valve? A cracked casing will still cause gas to leak out the overflow tube.

Did you remove the bowl and fill it up with water to see if it leaks out the overflow? I'd like to know how you've verified things.

+1. Find genuine Honda float needles.