4.0 B&S Engine - Runs Slow/Fast
Okay, I know the basics of mowers and am much more of a regular over on the Lawn Care Forum. I have a very basic mower: Murray 4.0 Briggs & Stratton, push mower. I put gas in it, change the oil every couple of years, I replaced the air filter and blade earlier this spring. 99% of the time I mulch mow, and have had no issues with the mower for the past 5-6 years.
The mower started acting up yesterday half way through mowing my lawn. The engine would "idle" much below the normal speed I'm used to, speed up to almost normal speed, then slow back down. The whole cycle lasted 2-3 seconds (1 second slow, 1 second normal idle). I checked the gas, the underneath, and the air filter. That was the extent of my mower knowledge so I gave up trying to fix it. I was able to finish the last 30 minutes of mowing, but it did this speed up/slow down cycle the entire last 30 minutes.