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dawg1 · Mar 10, 2007, 03:29 PM

I have an old Murray riding motor that won't run for more than a minute or two. If I clean the plug, I can get it to start fairly easy but will start to sputter and finally stop after a minute or two. I took the carb off and made sure the float wasn't stuck -- it appeared fine. Running the mower with the air filter off, I can see down into the carb -- it runs fine until gas pours into the side of the carb through this hole on the side. It then sputters and usually shuts off. The hole is attached to a short rubber tube that connects to the motor. I don't know enough about this to know what to do next. Is my float sticking causing too much fuel to dump somewhere? Should I get some carb cleaner and soak the whole thing? Thanks.

newaukumdon · Mar 10, 2007, 04:11 PM

Yep! All of the above. Get some carb cleaner and replace the needle seat as well as float. The crankase is filling up with fuel more than likley also. Be sure and change or at the very least check oil.

Don

dawg1 · Mar 10, 2007, 06:41 PM

This carb has one of those brass seats. How do I get it out?

newaukumdon · Mar 10, 2007, 07:51 PM

I would not worry about the seat, the wear component is the needle. Some will have a steel needle and rubber seat.

Don

dawg1 · Mar 11, 2007, 07:54 AM

Don -- thanks for the help.
Do I need to purchase the carb kit (Briggs 394698) or just buy the needle and float separately. I am not sure if the carb kit contains all of that. Do you know?

newaukumdon · Mar 11, 2007, 10:46 AM

I would buy the kit. It will not include float but will have all the gaskets and "O"rings. Will also have High speed jet I believe, order float seperatly.
Don

dawg1 · Mar 11, 2007, 11:45 AM

I am getting the kit Monday as you suggested. I am just curious though -- I took apart the bowl, float, etc again. The float doesn't have any fluid in it and seems to go up and down quite freely. It is also sitting parallel to the gasket when upside down. I took the float needle out too -- it appears OK to me. My question is, even if the needle and seat isn't perfect, how is it that a big splash of gas gets dumped? Would a splash of fuel big enough to cut the engine off be caused by an imperfect needle/seat? I'm definitely going to try the new parts but just want to know how this stuff works. Thanks again.

newaukumdon · Mar 11, 2007, 12:03 PM

If the float does not function properly it will not stop the fuel from overflowing into the throat. Some of the floats are a fiber mesh or poly composite and the do not look to hold fluid but after sitting in fuel they will sink. If you are certain yours is good leave it alone. The only way fuel can enter the system is through the inlet needle. Sometimes if the system is not venting it can push large amounts of fuel past the needle as well.

Try it without the fuel cap on.

Don

dawg1 · Mar 11, 2007, 06:10 PM

My float is the brassy looking metal/alloy one. It definitely doesn't have any fluid in it. After cleaning everything again today, it will crank and run OK for several minutes. Then you can gradually start to hear the engine sputter followed by fuel dumping into the carb. The engine will then usually die. The plug is covered in oil or whatever -- I guess this is the result of the excess fuel (?).
I was asking in the previous question how a worn tip on the float needle causes a big flood of gas? It seems like just a little extra gas would seep through on a worn tip. Rather, does the extra gas collect somewhere during the time it is running OK and then dump all at once through that black tube (on the side) back into the carb? Just curious about this...
I'll also try running it with the gas cap off. If that solves the prob, what do I replace? Is the venting through the gas cap itself?
Thanks again.

newaukumdon · Mar 11, 2007, 06:23 PM

You are describing a classic float issue, is the float traveling free? A lot of fuel can come up when the needle leaks or float sticks. I understand your question and realize it is a little odd to have that much fuel in the throat but there is no other way.

The tank vents from the cap. I had a vent issue a while ago and fuel just poured into carb like a gysser.

Don

dawg1 · Mar 11, 2007, 06:59 PM

Yeah -- the float is traveling up and down super freely. I'll get the parts hopefully Mon or Tues and report if that fixed it.
I'll be sure to try the gas cap thing too.

newaukumdon · Mar 11, 2007, 07:27 PM

I did forget to ask about air filter, is it clean and dry? Try running without it. Fuel can soak it and it may look good but will choke the engine out.

Don