Author Options:

What is wrong with my carburetor? Answered

AENL wisconsin motor 9.2 hp. 163e Zenith Carburetor. Everything has been rebuilt. I did most of the work myself. I started it for the first time, it fired right up. Then stopped after a minute. I noticed it was flooding...badly. fuel was leaking out of the carburetor by the intake. I then pulled the cord a couple more times and now it is leaking gas through the exhaust port. What happened? Float to high? I set it to the gauge provide by the carb kit. It was pretty close to right on. What next?


+2 (1 each for iceng and Re-design)

Constant leaking of fuel like that is indicative of a float valve that is, in some way, stuck open. Shut off the fuel line, drain the fuel from the carb, disassemble and verify the correct operation of the float and needle valve along with any associated linkages.

Make sure that the needle/seat assembly is clear of foreign objects (iceng) and not damaged or bent (Re-design).

Make sure that the float assembly is not binding/is sitting correctly in the pivot slots of the carb housing (Re-design).

When you are checking, you can put fuel in the bowl to make sure that when the float is up at the correct height, it closes the needle all the way. If it is open at all, you will have fuel leaking out of the feed line [inlet] (which, even though it is below the bowl level, would allow fuel to flow through the intake manifold/fuel outlet because the fuel tank is higher than the carb - "gravity feed"). If you have it closed all the way, say by pushing it closed with your finger, and it still leaks, you'll need to replace the needle and seat.

As for the fuel coming out of the exhaust port, take out the spark plug, give the engine a few spins and let it sit that way for at least 10 minutes to give the extra fuel a chance to evaporate. When you put it all back together, don't forget to check the oil in the crankcase. If it has any smell of gasoline to it at all, drain and replace with fresh oil. Oil contaminated with gasoline is not good for the engine.


Yes, I did see this thread. My engine started right up after the carb rebuild, then ran for about a minute, flawless. Then I started to notice fuel coming out of the carb intake. Stopped the engine, analysed the situation, and tried to re-start. Fuel went into the exhuast manifold.

To see if the float is good, put enough fuel into a plastic container to enable "floating" of the float. Place float in fuel. Does it float? If yes, continue on...
Push float below fuel level and hold there for about 10 minutes +-. Use something inert to hold it there, your fingers or hand is NOT a good idea. Take float out of fuel and give a quick dry off and see if there is any fuel inside the float. Shake and listen for any shloshing or "wet sounds" inside. If it is dry inside, it is good. Let us know what you find.

Are there any missing pickup tubes or anything in the carb? Airbleed needles that are loose? Anything that can let fuel go where it is not supposed to? I can't find a diagram of the carb, so I don't know the specifics, but all carbs work in very similar ways. If you have a link to the diagram, rebuild sheet, or other documentation, it would help greatly.


Ok, you all are correct! It was the float (sticking) and the float valve (not closing).
I took all youir information and began analyzing the situation. What I found out was that the rebuild kit provided a float valve and new spring. I replaced all the possible part in the kit (because I wanted it new again), but when I started having problems, I started going backwards and replace the old parts one by one, starting with the float pin, float valve...etc. What I found out by doing this was that the new float valve was higher than the old one, so it threw off the float from its original position. The float was getting jammed in the bowl. I could not replace the old float pin seat (because I messed it up trying to remove it) so I had to use the new seat. The old pin did not fit the new seat, so I had to use the new pin. This jammed my float to the bottom of the bowl and would not move...thus the gas leakage. I took the two halves of the carb and starting adjusting the float and finally got it to move when it was together. But the pin was still in the wrong position (to high) so I tweaked the spring until I could tell all should work. Well it did work. It started right up and now no leakage. I re-adjusted the Idle valve, then the high speed valve, then the govener. All is working fine now!!! Thanks for all the help!!!.

Thanks for the input. It really helped.

So, I took the carb apart and checked the float height and needle valve.
Float was in the wrong position, re-adjusted the float to correct position, re-assembled. Now no gas is getting to the carb.

Next, I readjusted the float to just allow the valve to let fuel into the carb (blew air thru the fuel inlet), turn the carb over (float upside down) valve closes (can't blow air thru), then re-installed. Fuel is leaking out of the carb.

Maybe float not working? How do I check this?

Now on the 5th re-assemble, and I have learned alot about this carb, but to no avail. Carb still leaking gas at the intake connection, where the choke is located. Choke is in the horizontal layout.


6 days ago

Did you replace the fuel pump? Check to make sure the PSI of the fuel pump does not exceed the specifications of the carb.

my goped will start up but wen i give it gas it bogs out


6 years ago

Did you check the piston rings or cylinder wall for scratches.

How clean was your fuel ?

Dirt could lodge in the float pin causing your flooding problem.


Float for sure (or a proper-leak).


Yup! see above for explanation. Thanks for the help.

I'm glad that you fixed it, thanks for the explanation.


Glad you solved the problem. Sometimes carbs can be a real pain when the replacement parts aren't quite right. I had a Rochester Quadrajet that I could only get parts for on-line. That thing was a right b**ch to get correct. I ended up using my knowledge of how a carb should work to get it running right - none of the settings in the rebuild kit directions or any other literature were right for it. But once it was set correctly, she really made that lil' V8 scream.

May your Wisconsin live a long and happy life with you.


The float pin or seat could be damaged. The float may be jammed when you put the car back together. Something is holding the float open allowing way too much gas into the intake.

You are correct, see above for the solution. Thanks for the help.