Briggs 4 HP carb on tank won't stay running

[neighborbill]

I have a Troy sickle mower with a briggs 4hp engine. I am having trouble keeping the engine running. I can spray starter fluid in the carb and it runs a bit then stops. I can spray again and it starts. When it wants to die I spray the starter fluid again and it keeps running. Once I stop the spraying it quits running. I"ve also left it sit for a day or two pulled the starter and it ran perfect, but only for a short while before stopping again. The spark plug is pretty black . Not wet, but carboned up.
I've never seen the carb attached to the tank before. Seems like a weird set up. I was looking for a fuel pump of some sort and thought this might be the problem. I don't see any fuel pump.
Any advise?
Bill

 

[grewal01]

I've got the same problem with a 6 hp Tecumpseh. I've checked the jets to be sure they are clear, also confirmed carb bolts and intake manifold bolts are tight. Seems carb will not draw fuel to the throat. I can sometimes keep it running a little while by almost completely covering the carb intake (like a "super choke"). I'll post my problems, and see if I get any answers- if so, I'll give the info to you.

 

[neighborbill]

I've got the same problem with a 6 hp Tecumpseh. I've checked the jets to be sure they are clear, also confirmed carb bolts and intake manifold bolts are tight. Seems carb will not draw fuel to the throat. I can sometimes keep it running a little while by almost completely covering the carb intake (like a "super choke"). I'll post my problems, and see if I get any answers- if so, I'll give the info to you.

Great I appreciate that.

 

[grewal01]

Hi,

Here's the sum of what I know and what I've just learned- if the carb had a bowl with a screw (jet) in the bottom, remove the jet screw and see if a continuous gas leak occurs- if so, gas is getting to the jet body, if not, the little feed hole in the jet body could be plugged (as was mine). You remove the valve body (which holds on the bowl) with a wrench. The feed hole is in the side of the housing (in the threads). If no gas leaks out, then either the float valve is plugged or the gas line is plugged. Also, after you remove the valve screw from the housing, make sure the housing hole (where the valve seats) is clear.

Hope this helps.

 

[Rivets]

There are two types of carbs mounted on the tank. One has the fuel pump mount on the side of the carb and the other has the pump mounted between the carb and the tank. I suspect that you have the second one. Remove the tank from the engine, remove the carb from the tank carefully. You will find a gasket, diaphragm and spring under there. Notice which direction they come off. You will notice that the carb have a long pickup tube and a short nozzle with a screen on it. The tank will have a small reservoir where the nozzle goes in. That may have dirt in it. Take the gasket and diaphragm to your repair shop for a replacement. Install the way you removed them. Install the tank. I think this will solve your problem.

 

[Practical Consumer]

They are called suction lift carbs and are common on small B&S engines. As mentioned above to clean them you just unscrew them from the tank and carfully remove the gaskets and spring. there are actually 2 gaskets (one thick one and one thin one). The thick one goes against the carb and the thin one against the tank. This is important because the thin gasket acts like a diagraphm pump and pumps fuel up from the tank. If your gaskets are damaged in any way get new ones. Spray carb cleaner in all the holes and tubes. The longest tube has a screen on the end of it. Make sure it is clean.
Good Luck!
The Practical Consumer | Push Lawn Mowers

 

[neighborbill]

Thanks guys! I got a pretty good picture of what to do now.
Very informative.

Bill