Valve Seats - Toro Groundsmaster 300 Series Service Manual

Valve Seats (Fig. 57, 58)
1. Check the valve seat for damage and signs of incor-
rect contact.
2. If the valve seat is defective, the seat can be re-cut
to the dimensions shown.
3. After cutting new valve seats, lap the valve to the seat
using the lapping compound. After lapping, thoroughly
clean the valve seat and valve areas to remove any
traces of lapping compound. To verify that the valve face
is making proper contact to the valve seat, lightly coat
the valve seat area with Prussion blue, install the valve,
rotate the valve 1/4 turn while holding it down and then
bring it back to the original position. Remove the valve
and examine the valve seat. The valve seat should show
an even wear pattern from contact with the valve. Ex-
amine the valve. The dye should be evenly distributed
around the valve and in the center of the valve face.
Cylinder Head Overhaul Page 4 - 50
Figure 57
Dimension of valve seat
Figure 58
Correction of valve seat
Groundsmaster
®
300 Series