Bolens 643C Service Manual

NOTE: Stand behind 
the tiller as if you were 
going to operate it. Your 
right hand corresponds 
to the right side of the 
tiller; your left hand 
corresponds to the left 
side of the tiller.

This unit is shipped 
without gasoline or oil 
in the engine. Fill up 
gasoline and oil as 
instructed in the accom-
panying engine manual 
BEFORE operating your 
machine.

NOTE: This operator’s 
manual may cover 
various models of tillers. 
The units illustrated 
may vary slightly from 
your unit. Follow only 
those instructions which 
pertain to your model 
number.

Carefully follow these assembly steps to correctly prepare your tiller for use. It is recommended that you read this 
Section in its entirety before beginning assembly.
NOTE: Various tiller models are presented in this manual. Use only the information appropriate 
for your tiller model. Engine styles vary by model. Your engine may appear differently than 
those illustrated in this manual.

Figure 2-1:  To identify length of screws, place screw on 
template as shown and measure distance between bottom of 
screw head and tip of screw.

(2)  1/2” open-end wrench* 

(2)  9/16” open-end wrench* 

(1)  3/8” open-end wrench* 

(1)  Large adjustable wrench 

 

(Models 643B & 645A only) 

(1)  Scissors (to trim plastic ties) 

(1)  Ruler (for belt tension check) 

(1)  Block of wood (to support tiller when removing  

 

wheels) 

(1)  Tire pressure gauge (for models with pneumatic 
 

tires) 

(1)  Clean oil funnel 
(1)  Motor oil. Refer to the Engine Owner’s Manual for  
 

oil specifications and quantity required. 

  * Adjustable wrenches may be used.

STEP 1: UNPACKING INSTRUCTIONS
NOTE: While unpacking, do not severely bend any 
control cables.
1.  The tiller weighs approximately 133 lbs. Do not 

attempt to remove it from the shipping platform until 
instructed to do so in these Assembly steps. 

2.  Remove any packaging material from the carton. 

Remove any staples from the bottom of the carton and 
remove the carton from the shipping platform.

3.  Remove all unassembled parts and the separate 

hardware bag from the carton. Check that you have 
the items listed in the Loose Parts List (contact 
your local dealer or the factory items are missing or 
damaged). 

NOTE: Use the screw length template (Fig. 2-1) to 
identify screws.

Qty.    Description
1 

Handlebar Support (see A, Fig. 2-2) 

1 

Handlebar Assembly (see K, Fig. 2-2)

 

4 

Hex hd. screw, 5/16-18 x 1-1/2” 

2 

Hex hd. screw, 3/8-16 x 3/4” 

2 

Flat Washer, 3/8” 

4 

Split lock washer, 5/16” 

4 

Hex nut, 5/16”-18 

2 

Hex locknut, 3/8”-16

*Models 643B & 645A only

IMPORTANT: Motor oil must be added to the engine 
crankcase before the engine is started. Follow the 
instructions in this Section and in the separate Engine 
Owner’s Manual.
STEP 2: ATTACH HANDLEBAR
1.  Loosely attach the legs of the handlebar support 

(A, Fig. 2-2) to the inner sides of the tiller frame 
using two 3/8”-16 x 3/4” hex hd. screws (B), 3/8” flat 
washers, and 3/8”-16 hex locknuts.

2.  Using two 5/16”-18 x 1-1/2” screws (C), 5/16” split 

lock washers (D) and 5/16”-18 hex nuts (G), loosely 
attach the handlebar support (A) using the upper 
holes. Tighten the two screws securely.