I have a 15.5 Briggs and Stratton on my riding mower, and while I'm cutting, It sputters and dies.?

Question

I doesn't happen when it's cold, but when it warms up and usually with the blades engaged, it starts to sputter and then turn off. If I disengage the blades while it's sputtering, sometimes it will stay on and idle fine again, until of course I reengage the blades, and then it turns off again. It usually starts right back up. I've replaced the in-line fuel filter and hoses which were worn, and cleaned out the gas tank, but no luck. I hope someone can help me with this problem.

Answer 1

The fast idle mechanism may be broke or bent. You also may be having some fuel pump problems. When you engage the blades it places torque on the engine. If the fast idle doesn't kick in, then it is working off of the same amount of fuel. Same with the pump. Maybe the fast idle is working, but the pump can't keep up. The pump would be my guess if you can run the thing more than 30 seconds or so before it dies out. If it's been more than 3-5 years, definetly do the carb first. I would say this is probably a 2 job on a 1-5 scale, if your handy.

God Bless

Answer 2

It could be that you have a simple gas cap problem. There is a small pinhole or holes in the gas cap designed to let air flow thru the lines. If the hole/holes are plugged the fuel system creates a vacuum and then eventually without air to mix with the fuel the engine will cut out and stall. Take off the gas cap and check to see if air can flow thru. The hole/holes will be small.
Or you may want to shoot some carb cleaner thru the carb. it may have something gunking up the system. These are a couple of simple suggestions. The carb may need to be rebuilt but I would try these other options first.
I hope this works for you, nothing like getting a $5.00 repair bill for your mower. LOL
Since you say that it runs better with the blades disengaged again, that would sound like it has an issue with running 'under load', which makes me think carburetor first. But lets hope thats wrong.
Good luck

Answer 3

This is a gravity flow fuel system and a float controls the amount of gas level in the carb .

Take and remove the bowl from the bottom of the carb. You have a sticking float.

I have a 14.5 HP BS on my 38 inch cut mower and my sediment bowl had nothing in it. Mine would run at about 1/2 throttle without dying out. So to fix that sticking float I added a fuel cleaner to the gas tank when it was about only 1/3 full. I got the cleaner at an auto store. This fixed the sticking float. And now it will run at high throttle.

Incidently, this spring that float of mine stuck in open position and about 1/2 tank of gas ran down straight thru the valves and into the crankcase. I had to drain the oil and free up that float in the carb. Its not done it since and seems to run just fine again after I added the automotive carb cleaner to the gasoline.

Answer 4

Check the drive belts and pulleys for any binding or excess drag. Clean and lube the mower deck. Sounds like something in the drive mechanisms is overloading the engine.