Outdoor Power Equipment and Small Engines - toro 3521

1985 vintage toro snowblower with tecumseh engine , leaks gas out the carb where the air filter is supposed to be. have rebuilt carb. replaced bowl seal gasket and high speed adj. screw gaskets and the screw itself. still leaked. finally just purchased new carb and it took a couple of days but now this one still leaks also . help !

Was your "new" a complete carb or a service carb? The most likely cause of what you are describing a leaky float with gas in it. Did the new carb come with a new float or did you use the old one?

I agree, either the float has gas in it, and/or the needle and seat are not sealing and need replacing.

I suspect that if you took the primer hose off the carb and waited, the flooding would cease. The old primers had an unseen vent in the edge which over time will plug up. This will keep the carb from venting which makes it act like the primer is putting enough pressure on the top of the fuel forcing it out and the float drops enough to add more fuel to the carb. Two things you can do. First remove the prime hose and leave it stand for a while to be sure. Then you can either take a hot needle and make a hole in the center of the primer rubber or purchase a new primer. The new replacement primers come with a hole in them for this engine. :wall: The boss had a hard time with this also when I showed him the results using a new primer button. He was telling the customers to install a fuel shutoff valve and always turn it off. Any way good luck and hope this takes care of your problem.

Was your "new" a complete carb or a service carb? The most likely cause of what you are describing a leaky float with gas in it. Did the new carb come with a new float or did you use the old one?

yes a completely new carb and bowl and float and seals adj. screws. etc.

I suspect that if you took the primer hose off the carb and waited, the flooding would cease. The old primers had an unseen vent in the edge which over time will plug up. This will keep the carb from venting which makes it act like the primer is putting enough pressure on the top of the fuel forcing it out and the float drops enough to add more fuel to the carb. Two things you can do. First remove the prime hose and leave it stand for a while to be sure. Then you can either take a hot needle and make a hole in the center of the primer rubber or purchase a new primer. The new replacement primers come with a hole in them for this engine. :wall: The boss had a hard time with this also when I showed him the results using a new primer button. He was telling the customers to install a fuel shutoff valve and always turn it off. Any way good luck and hope this takes care of your problem.

believe the primer rubber has hole in center already, will dbl. check. gas tank has shut off but always have to remember to use it i guess after plowing. just did not think was normal for gas to leak even if supply was not shut off after every use !

It is not normal, just like a toilet running is not normal. It is the same concept. The float lifts the needle into the seat and stops the flow of gas.

Either

1) Float has gas in it
2) Seat is hard and not allowing needle to seat
3) Piece of debris between seat and needle
4) Carb is pitted or scratched in orifice where seat is.
5) Float is not adjusted properly to allow proper seating.

That's about it none of the reasons are difficult to repair.