My 18 hp B&S on my Garden Tractor won't continue to run. It is about 10 years old. I mowed the grass a few weeks ago and it ran fine until I was almost done with the 1 acre mow job. It started to lose power as I was climbing a small hill in the yard, then it died. I was able to restart it, but I had to close the choke fully in order for it to stay running, and the it only ran for a short distance before it shut off again. This week, I could not get it to stay running for more than a few hundred feet before it shuts off like it no longer got gas or the key was shut off.
What I did: Pulled the fuel filter off and blew through it from both ends. No obstructions, and I could see the screen was clean inside. I blew through the gas line that goes to the gas tank and was able to blow bubbles in the tank. I replaced the fuel filter with a piece of tubing, just in case it was the filter. I removed the gas line from the carburetor and the gas ran out freely. I pulled the cover off the carburetor and checked the diaphragms. No holes, tears or problems. I ran it with the air cleaner off and the in-line fuel filter removed. No difference. The gas is not old and the tractor is used year round for lawn mowing and snow blowing.
As far as I can figure, it runs out of gas or perhaps heats up to where it seizes up. Is there an oil pump that may have gone bad?