Purchase 1 can each of Liquid Wrench Brand Penetrating & Lubricating oil, make sure cans have straws to insert into nozzle, use penetrating oil first & let it soak for a while. Use lubricating oil after it loosens up & spray down the other three, I would repeat lubricating adjusters 2 or 3 times a season. You can remove spark plug boot from plug for SAFETY & place 2x6 or similar pieces of wood under middle of deck, taking weight off wheels, so you can work adjusters back & forth loosening them up.
