Gas leaking out of carburetors

Brian84

Brian84

Well-known member
I just recently bought an old Kawasaki S3 2-stroke and I've been trying to get it running properly since buying it. I changed some fouled spark plugs, and the bike has been running decently well since, except that while I was driving it I noticed gas started pouring out of the carbs. I stopped to check and it seemed like the problem was gone, so I drove back home without seeing more gas drip out. I just tried to start it again, and gas started pouring out all over my parking space :(.

I noticed two things:

1) The middle air filter (pod filters) has a hole in it, and it looks like the cap has fallen off. I had been driving it like this for a short while, so I hope I didn't introduce dirt and debris into the engine.

2) The middle carb and one of the outer ones is very loosely connected to the engine intake.

I patched up the hole in the filter with some duct tape as a temporary fix, but am still trying to figure out what is causing the gas leak? Is it possible to fix this without removing the carbs? It's parked in my parking garage, so I'm trying to avoid doing too much work on it while it's parked there.
 
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Brian84 said:
IMG_20140411_183153.jpg
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So could be a number of things

stuck floats, Crap in the float valve or a faulty petcock.. but i'm guessing its just 1 carb?

Try taping firmly on the carp with the handle of a screw driver. If its a stuck float it might fallout from doing this (but it will probably happen again)
You need them off the bike and disassembled
 
Bad or stuck float, or dirt in float seat/needle
 
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Float is stuck, full of gas, or not seating properly dues to crap in there (checked the parts diagram and there is a float in each). Pull them off clean them and inspect them.

There should not be a hole in the pod. Replace....
 
So I found the cap for the pod filter, which had fallen off. That problem is solved.

Still having gas leaking from one of the carbs. I took all of them off the bike and opened up the floats; they all seemed fine. None of them were stuck. They looked really clean too, like they'd been cleaned fairly recently.
 
I'll have to take them off the bike again. They looked like they were in good shape, but I'll have to be more thorough. At least I'm pretty sure I know which carb is the problem now.
 
With the carbs on the bike and hooked up to the gas line: remove 1 float bowl. Turn on the fuel petcock. Gas should be leaking out of the bottom of the carb. Gently push upwards on the floats (as gas would do if the bowl were there and filling up.) The flow of gas should stop.

Repeat with other carb.

if the gas flow doesn't stop, then either the floats are bad (too heavy), the floats are not adjusted properly, or the float needle or seat are damaged or dirty.
 
Schneller said:
With the carbs on the bike and hooked up to the gas line: remove 1 float bowl. Turn on the fuel petcock. Gas should be leaking out of the bottom of the carb. Gently push upwards on the floats (as gas would do if the bowl were there and filling up.) The flow of gas should stop.

Repeat with other carb.

if the gas flow doesn't stop, then either the floats are bad (too heavy), the floats are not adjusted properly, or the float needle or seat are damaged or dirty.
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YUP do this..on my GS i can actually take the float needles out has to do this the first time i fired her up due to rust from the tank getting in there. Filters helped me..
 
Actually, I misspoke.

If you do this with very light pressure and the gas flow stops, then the float is bad (too heavy) or float height is not adjusted properly.

If you do this with very light pressure and the gas flow does not stop, then the float needle and/or seat is damaged or dirty.
 
So it looks like it was the float height that was the problem. Going to reinstall the carbs today and see if it's fixed. I get anxious every time I see a motorcycle on the road and I can't ride, so I'll be very happy to be back on the road ;).
 
Great!
 
Brian84 said:
So it looks like it was the float height that was the problem. Going to reinstall the carbs today and see if it's fixed. I get anxious every time I see a motorcycle on the road and I can't ride, so I'll be very happy to be back on the road ;).
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Thanks for coming back to the the thread and letting us know.
 
Gas leaking from the same carb again. I think it's the float height, yet again. Is there any reason this would keep happening? Should I replace the float itself?
 
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