MTD 760, 770 Troubleshooting, Problem, Cause, Remedy

Troubleshooting 8

Problem		Cause		Remedy
Engine fails to start	1.	PTO/Blade engaged.	1.	Place knob (or lever) in disengaged (OFF)
				position.
	2.	Spark plug wire disconnected.	2.	Connect wire to spark plug.
	3.	Fuel tank empty, or stale fuel.	3.	Fill tank with clean, fresh (less than 30 days
				old) gas.
	4.	Choke not activated.	4.	Place the throttle control in CHOKE position.
	5.	Faulty spark plug.	5.	Clean, adjust gap or replace plug.
	6.	Blocked fuel line.	6.	Clean fuel line and replace fuel filter.
	7.	Engine flooded.	7.	Crank engine with throttle in FAST position.
	8.	Parking brake not engaged	8.	Engage parking brake.
	9.	Throttle control lever not in correct starting	9.	Place throttle lever to FAST position.
		position.
Engine runs erratic	1.	Unit running with CHOKE activated.	1.	Move the throttle contol out of the CHOKE
				position.
	2.	Spark plug wires loose.	2.	Connect and tighten spark plug wire.
	3.	Blocked fuel line or stale fuel.	3.	Clean fuel line; fill tank with clean, fresh
				gasoline and replace fuel filter, is so equipped.
	4.	Vent in gas cap plugged.	4.	Clear vent or replace cap if damaged.
	5.	Water or dirt in fuel system.	5.	Drain fuel tank. Refill with clean, fresh
				gasoline.
	6.	Dirty air cleaner.	6.	Replace air cleaner paper element or clean
				foam precleaner, is so equipped.
Engine overheats	1.	Engine oil level low.	1.	Fill crankcase with proper amount and
				weight of oil.
	2.	Air flow restricted.	2.	Clean grass clippings and debris from around
				the engine’s cooling fins and blower housing.
Engine hesitates at high	1.	Spark plug gap too close.	1.	Remove spark plug and reset the gap.
RPM
Engine Idles rough	1.	Spark plug fouled, faulty or gap too wide.	1.	Replace spark plug. Set plug gap.
	2.	Dirty air cleaner.	2.	Replace air cleaner element and/or clean
				pre-cleaner, if so equipped.
Excessive vibration	1.	Cutting blade loose or unbalanced.	1.	Tighten blade and spindle. Balance blade.
	2.	Damaged or bent cutting blade.	2.	Replace blade.
Mower will not mulch grass	1.	Engine speed too low.	1.	Place throttle in FAST (rabbit) position.
	2.	Wet grass.	2.	Do not mulch when grass is wet.
	3.	Excessively high grass.	3.	Mow once at a high cutting height, then
				mow again at desired height or make a
				narrower cutting swath.
	4.	Dull blade.	4.	Sharpen or replace blade.
Uneven cut	1.	Deck not leveled properly.	1.	Perform side-to-side deck adjustment.
	2.	Dull blade.	2.	Sharpen or replace blade.
	3.	Uneven tire pressure.	3.	Check tire pressure in all four tires.

28