Connecting Rods - Mercury Optimax 115 Service Manual

End Bearing Bleed System
1. Check rubber bleed hoses. Replace any hose that is cracked, cut or deteriorating.
2. Check operation of lower end cap check valve. If valve is working properly, air can be
drawn thru check valve "one way" only. If air can pass thru a check valve both ways,
valve is not working properly and must be replaced.

Connecting Rods

1. Check connecting rods for alignment by placing rods on a surface plate. If light can
be seen under any portion of machined surfaces, if rod has a slight wobble on plate,
or if a 0.002 in. (0.051 mm) feeler gauge can be inserted between any machined sur-
face and surface plate, rod is bent and must be discarded.
2. Overheating: Overheating is visible as a bluish bearing surface color that is caused
by inadequate lubrication or excessive RPM.
3. Rust: Rust formation on bearing surfaces causes uneven pitting of surface(s).
a -
4. Water Marks: When bearing surfaces are subjected to water contamination, a bear-
ing surface "etching" occurs. This etching resembles the size of the bearing.
5. Spalling: Spalling is the loss of bearing surface, and it resembles flaking or chipping.
Spalling will be most evident on the thrust portion of the connecting rod in line with the
"I" beam. General bearing surface deterioration could be caused by or accelerated
by improper lubrication.
a -
90-855347R1 JANUARY 1999
Pitting
Spalling
a
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a
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POWERHEAD
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