New Engine Break-In - Yanmar 2YM15 Operation Manual

PRODUCT OVERVIEW

New Engine Break-In

As with all reciprocating engines, the way
the engine is operated during its first 50
hours of operation plays a significant role in
determining how long it will last and how well
the engine will perform over its lifetime.
A new Yanmar diesel engine must be
operated at suitable speeds and power
settings during the break-in period to allow
the sliding parts, such as piston rings, to
break in properly and to stabilize engine
combustion.
During the break-in period, the engine
coolant temperature gauge should be
monitored. The temperature should be
between 71˚ and 87˚C (160˚ and 190˚F).
During the first 10 hours of operation, the
engine should be operated at maximum rpm
minus 400 to 500 rpm (approximately 60 to
70% of load) most of the time. This will
ensure the sliding parts break in properly.
NOTICE: During this period, avoid
operating at maximum engine speed
and load to avoid damaging or scoring
sliding parts.
NOTICE: NEVER operate at WOT (wide
open throttle) for more than a minute at
a time during the first 10 hours of
operation.
Do not operate the engine at low idle or at
low speed and light load for more than
30 minutes at a time. Since unburned fuel
and engine oil will adhere to the piston rings
when operating at low speeds for long
periods, this will interfere with proper
movement of the rings and the diesel fuel
consumption may increase. Low idle speed
does not allow break-in of sliding parts.
If operating the engine at low speed and light
load, you must race the engine to clean the
carbon from the cylinders and the fuel
injection valve.
10
Perform this procedure in open waters:
• With the clutch in NEUTRAL, accelerate
from the low speed position to the high
speed position briefly.
• Repeat this process five times.
Once past the initial 10 hours until 50 hours,
the engine should be used over its full
operating range, with special emphasis on
running at relatively high power settings.
This is not the time for an extended cruise at
idle or low speed. The boat should be
operated at maximum speed minus 400 rpm
most of the time (approximately 70% load),
with a 10 minute run at maximum minus 200
rpm (approximately 80% load) every
30 minutes and a 4 to 5 minute period of
operation at WOT (wide open throttle) once
every 30 minutes. During this period, be sure
not to operate the engine at low speed and
light load for more than 30 minutes. If
operating engine at low speed and light load
is necessary, race the engine after low idle
operation.
To complete engine break-in, perform After
Initial 50 Hours maintenance procedures.
See After Initial 50 Hours of Operation on
page 52.
YM Series Operation Manual
© 2007 Yanmar Marine International