Bolens 84 Service Manual

12

•

Disconnect spark plug wire.

•

Drain the gasoline from the lawn mower, or place a 
piece of plastic under the gas cap.

•

Tip the mower so that it rests on the housing. Keep 
the side with the air cleaner facing up. Hold the 
mower firmly.

•

Scrape and clean the underside of the deck with a 
suitable tool. Do not spray with water. 

•

Put the mower back on its wheels on the ground. If 
you had put plastic under the gas cap, make sure to 
remove it now.

A list of key maintenance jobs, required for good 
performance by the mower, is given below. Follow the 
accompanying engine manual for details. 

•

Change engine oil regularly, as instructed in the 
engine manual. Check oil level before starting 
engine every time.

•

Service foam filter in the air cleaner every 25 hours 
of use and replace the paper filter component every 
100 hours. You may have to service the air filter 
more frequently if you are operating the mower 
under extremely dusty conditions.

•

Clean the engine periodically. Remove dirt and 
debris with a cloth or brush. 

•

Clean the spark plug and reset the gap to .030” at 
least once a season. Refer to the engine manual for 
correct spark plug type.

•

Inspect muffler periodically, and replace if 
necessary. 

Periodically inspect the blade adapter for cracks, 
especially if you strike a foreign object. Replace when 
necessary.

•

Disconnect spark plug wire from spark plug.

•

Turn mower on its side making sure that the air filter 
and the carburetor are up.

•

Remove the bolt and the blade bell support which 
hold the blade and the blade adapter to the engine 
crankshaft. See Figure 12.

•

Remove blade and adapter from the crankshaft.

•

The blade can be sharpened with a file or on a 
grinding wheel. Do not attempt to sharpen the 
blade while it is still on the mower.

•

Follow the original angle of grind as a guide. Make 
sure that each cutting edge receives an equal 
amount of grinding to prevent an unbalanced blade.

•

The blade can be tested by balancing it on a round 
shaft screwdriver. Remove metal from the heavy 
side until it balances evenly. It is recommended that 
the blade always be removed from the adapter 
when testing for balance. 

•

Before reinstalling the blade and the blade adapter 
to the unit, lubricate the engine crankshaft and the 
inner surface of the blade adapter with light oil.

•

Be sure to install the blade with the side of the 
blade marked “Bottom” (or with part number) facing 
the ground when the mower is in the operating 
position.

•

Slide the blade adapter onto the engine crankshaft.

•

Place the blade on the adapter. Be certain the 
blade is aligned and seated on the blade adapter 
flanges.

•

Place blade bell support on blade. Make sure the 
notches on the blade bell support are aligned with 
small holes in the blade.

•

Replace hex bolt and tighten hex bolt to torque: 450 
in. lbs. min., 600 in. lbs. max.

Never tip the mower more than 

90 degrees in any directions and do not leave 
the mower tipped for any length of time. Oil can 
drain into the upper part of the engine causing 
a starting problem.

Damaged mufflers or spark 

arresters can create a fire hazard. Make sure to 
avoid muffler and surrounding areas while the 
mower engine is hot because temperature of 
these areas of the engine may exceed 150

o

 F.

When removing the cutting 

blade for sharpening or replacement, protect 
your hands with a pair of heavy gloves or use a 
heavy rag to hold the blade.

An unbalanced blade will cause 

excessive vibration when rotating at high 
speeds. It may cause damage to the mower, 
and could break causing personal injury.