Post by jeepsaffer on Jun 1, 2020 6:50:19 GMT -5
Hey Scout, I would appreciate your thoughts on a tiny carb leak I have.
I initially had a leak on a WO 636SA carb I had professionally cleaned, and I then rebuilt using a kit you sent me. The throttle body was a rebushed one you sent me. The carb works well, and the jeep drives well - idles at lower than 600rpm if I want it to, acceleration is good. However there is a tiny fuel leak after shutting down, that amounts to 1 drip every few minutes, or maybe every half hour. At this stage I can't determine exactly where the leak is coming from because the leak rate is so slow. It appears to be from the engine side of the float bowl where you can't see easily. The tiny weep/seep runs down to the bottom of the bowl, finds the low spot which I think is one of the rivets, and drips off onto the intake manifold on the firewall side. I have never actually seen it drip - it is that slow. But I can see it has been dripping because it has removed paint from my intake manifold. If I take clean white paper towel and wipe the bottom of the bowl in that area, I get a smudge of gas on the towel. Try again in 30 mins time and there is a new smudge of gas. Visually, from the fender, the carb looks dry and clean, which is why I think it is somewhere between the bowl and throat area where you can't see easily.
I thought it was a leaking rivet or one of the plug gaskets at the bottom of the bowl, so I tightened up everything that could be tightened up, but no change. It doesn't appear to be leaking out from the bowl cover or gasket area on the sides I can see.
I then changed back to a NOS carb that I had disassembled for cleaning. I put it back together again, adjusted the float tang ever so slightly with the correct 3/8" Carter tool, and reassembled. Exactly the same issue! Some leak, same rate, same hard to see places.
What's going on here? Is it the float bowl, and should I bend the tang to create just a little clearance between the bowl cover and float, or should the float and tool just be touching, or just not touching? Could such a small change in float level cause the fuel to be literally lapping at the top of the bowl? What would the downside be to having a hair breadths clearance between the float and the tool?
Take care,
Mike
I initially had a leak on a WO 636SA carb I had professionally cleaned, and I then rebuilt using a kit you sent me. The throttle body was a rebushed one you sent me. The carb works well, and the jeep drives well - idles at lower than 600rpm if I want it to, acceleration is good. However there is a tiny fuel leak after shutting down, that amounts to 1 drip every few minutes, or maybe every half hour. At this stage I can't determine exactly where the leak is coming from because the leak rate is so slow. It appears to be from the engine side of the float bowl where you can't see easily. The tiny weep/seep runs down to the bottom of the bowl, finds the low spot which I think is one of the rivets, and drips off onto the intake manifold on the firewall side. I have never actually seen it drip - it is that slow. But I can see it has been dripping because it has removed paint from my intake manifold. If I take clean white paper towel and wipe the bottom of the bowl in that area, I get a smudge of gas on the towel. Try again in 30 mins time and there is a new smudge of gas. Visually, from the fender, the carb looks dry and clean, which is why I think it is somewhere between the bowl and throat area where you can't see easily.
I thought it was a leaking rivet or one of the plug gaskets at the bottom of the bowl, so I tightened up everything that could be tightened up, but no change. It doesn't appear to be leaking out from the bowl cover or gasket area on the sides I can see.
I then changed back to a NOS carb that I had disassembled for cleaning. I put it back together again, adjusted the float tang ever so slightly with the correct 3/8" Carter tool, and reassembled. Exactly the same issue! Some leak, same rate, same hard to see places.
What's going on here? Is it the float bowl, and should I bend the tang to create just a little clearance between the bowl cover and float, or should the float and tool just be touching, or just not touching? Could such a small change in float level cause the fuel to be literally lapping at the top of the bowl? What would the downside be to having a hair breadths clearance between the float and the tool?
Take care,
Mike
