Question about 1993 kawasaki VN 750 Vulcan

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Replaced diaphram fuel valve and carbs ..cannot open fuel valve all the way without flooding engine. Excess fuel poars from carb assembly. Could there be some sort of problem with the vacuum system that controls fuel flow? Floats were adjusted.

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I would say the problem is in your carbys, with the float levels, or a sticky needle and seat. If you open the fuel valve, fuel will flow into the carbys, ans shut off once the correct level is reached. I think the problem is in your carbys, not the fuel valve. I would remove the carbys, take the bowel off the bottom, and check the needle and seat, and float levels. It is not recomended to change the float levels from standard.

Posted on Apr 27, 2010


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Fuel over flows thru overflow tubes only when motor is running. motor off ignition on it stops.

Your gas tank petcock is diaphram operated.
there is a vacuum line coming off the intake, that goes straightb to the petcock.
when you turn the motor over a vacuum is created, pulling the petcock diaphram back and allowing fuel to flow to your carburetor. when you turn the motor off the vaumm is gone and the spring behind the diaphram pushes it closed and stops the fuel flow to the carbs.

Now the reason the carbs are overflowing is because the floats valves are not closing, in other words the floats are sticking.
Usually a good carb clean will cure the problem, especially for that year.
the older ones usually require new float valves/seats that are usually found in a good carb rebuild kit. You shouldn't need one.

If your really broke try tapping on the bowls of the carburetor lightly, while the engine is running, sometimes the vibration will vibrate a particle loose that may be holding open the float valve.
if it works then the fuel should stop overflowing while running.

if you know how to work on it, try this, with the engine off.
open the carburetor drain screws so that fuel will run out the carb. drain. flush out the carb.
get a container to catch the gasoline.
while fuel is flowing tap the carb bowls a few times then closed the drain screws.
clean up any spilled gasoline .
start your bike.see if they stop leaking and the floats are closing.
if it still leaks, you'll need the cleaning.

Happy Riding
Best Regards
Big Al

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did you replace you diaphrams or just clean them, does it have a float bowl or just diaphram? sounds like during all you cleaning you did'nt adj the tab to the needle, therefore diaphram is not opening needle which is not giving gas to the carb. tab should be flush with carb body and when you push on it needle should move to open and let fuel in, good Luck

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Hi,i have a stihl 026 chainsaw with a bad flooding problem.I have checked the inlet needle in the carb and it is not stuck.I replaced the diaphrams and double checked that i installed them properly.After...

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you mentioned carb has been re-kited

did you fit the pump diaphram on carb then the pump gasket ?

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but sounds like a faulty breather


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1 Answer

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