Mercury MerCruiser Product Applications Manual page 82

• If a waterlift/collector system is used, the waterline is defined as the waterline inside
the collector. All measurements must be taken from that waterline to measure exhaust
elbow weight.
WATER LIFT MUFFLER
When using water lift mufflers, Mercury MerCruiser recommends the following:
• Install mufflers per Mercury and the exhaust system manufacturer's specified distance
below the top of the exhaust elbows to avoid water ingestion problems. Use the exhaust
elbow risers if needed to obtain the specified distance.
• The muffler riser must also exceed both Mercury's and the exhaust system
manufacturer's specified distance above the waterline to prevent the muffler from filling
with water.
• Install a siphon break (vacuum valve) in the exhaust cooling water circuit if the exhaust
elbows or muffler are at or below water level. Refer to Mercury's and exhaust system
manufacturer's recommendations.
• Provide a drain to the drain muffler.
b
90-863758060 AUGUST 2006
Typical vertical water lift muffler
a - Minimum exhaust elbow height
with maximum load
b
Typical horizontal water lift muffler
a - Minimum exhaust elbow height
with maximum load
a
24866
b - Clear hose for measuring waterline
a
24867
b - Clear hose for measuring waterline
Exhaust System
Page 6A-13