I have a Toro model 74219 that I have had to multiple shops trying to fix an issue with the engine. The mower surges at times and other times runs smoothly. The throttle assembly has been replaced, oxygen sensor, coils, etc. The last place said they talked to Kohler and they didn't know. After the last place charged me close to $400, it does seem to run better at times but then out of the blue starts to surge again, usually after shutting it off for a minute. Could the fuel pump be the issue? I tried loosening the wires and tapping on it the last time it died and it started up long enough to get it to the garage. Any thoughts?
Random fuel starvation can also be caused by debris building up in the outlet pipe in the fuel tank and if yours has multiple fuel tanks then around the change over valve as well.
Just done one, four trips to the dealer, got the owner to blow back up the fuel lines with low pressure air and the fuel cap off.
He rang back a few days latter had mowed his 5 acres without a hitch and was now going to remove the fuel tank to clean it properly.
