Yamaha MM700A Manual page 180

174
Hoses
Hoses deteriorate with age and should be replaced peri-
odically or whenever they start cracking or leaking. To be
safe, replace the hoses every 2 years. Loss of coolant
causes the engine to overheat and results in excessive
damage.
Whenever removing any component of the cooling sys-
tem, inspect the hoses(s) and determine if replacement is
necessary.
Inspection
1. Check all the cooling hoses for flexibility and softness
after the engine has cooled. Replace hoses that are brittle
or hard. Also check hoses for cracks, abrasions, cuts or
other conditions that might cause a leak.
2. When the engine is hot, examine the hoses for swelling
along the entire hose length. Eventually a hose will rup-
ture if softened by oil or heat.
hose clamps for possible leakage.
Replacement
Perform hose replacement when the engine is cool.
1. Drain the cooling system as described in Chapter
Three.
NOTE
1
Note the routing and any clamps supported
by the hoses. There may be some covers that
protect the hose from being damaged by
rubbing against another item. Make sure
these guards are installed on the new hose.
2. Loosen the hose clamps from the hose to be replaced.
Slide the clamps along the hose and out of the way.
3. Twist the hose end to break the seal and remove from
the connecting joint. If the hose has been on for some
time, it may have fused to the joint. If so, insert a small
pick tool or screwdriver between the hose and joint. Work
the tool around the joint and carefully pry the hose loose.
Excessive force applied to the hose during
removal coulddamage the connectingjoint.
4. Examine the connecting joint for cracks and other
damage. Repair or replace parts as required. If the joint is
good, remove any rust with a wire brush.
5. Inspect the hose clamps and replace as necessary.
6. Slide the hose clamps over the outside of the hose and
install a hose connecting joint. Make sure the hose clears
all obstructions and is routed properly.
NOTE
I f it is difficult to install a hose on a joint,
soak the end of the hose in hot water for ap-
proximately 2 minutes. This softens the hose
and eases installation.
tion the clamps back away from the end of hose slightly.
Tighten the clamps securely, but not so much that they
damage the hose.
8. Refill the cooling system as described in Chapter
Three. Start the engine and check for leaks. Tighten the
hose clamps as necessary.
CHAPTER EIGHT