Yamaha F150B Service Manual page 431

TIP:
The test run is part of the break-in operation.
Break-in
Run the engine under load (in gear with a
propeller installed) for 10 hours as follows.
1. For the 1st hour a of operation, run the
engine at varying speeds up to 2000 r/
min or approximately half throttle.
2. For the 2nd hour b of operation,
increase engine speed as much as
necessary to put the boat on plane (but
avoid full-throttle operation), then back off
on the throttle while keeping the boat at a
planing speed.
3. Remaining 8 hours c, run the engine at
any speed. However, avoid operating at
full throttle for more than 5 minutes at a
time.
4. After the 1st 10 hours, operate the
engine normally.
a b
A
0 1 2
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Hour
After test run
Do not perform this procedure on land
while the engine is running. The water
pump may be damaged and severe engine
damage from overheating can take place.
1. Check for water in the gear oil.
2. Check for fuel leakage in the cowling.
3. Flush the cooling water passage with
fresh water.
c
10
TIP:
When using the flushing device (flushing
hose joint adapter), flush the cooling water
passages without starting the engine.
Predelivery check
10-8
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