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What should the compression range be for a Yamaha F225? I am in the process of pruchasing a boat with this motor. The compression came back with 5 cyclinders in a range of 175-172 and 1 at 155. Is this ok or should I be concerned? Also had it scoped for the exhaust corrission issue and it has the problem and that needs to be repaired. Engine only has 248 hours.
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JMB -
Leak down test would be best on a 4 stroke instead of compression test -
comnpression test on that motor is equivalent to teats on a boar hog.
we want leak down percentage numbers.Comment
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How to...... "leak down test?Comment
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by using a device called a leakdown tester and air typically at 100 PSI.
the cylinder is theoretically seald at TDC on compression stroke.
it injects a known pressure and monitors how much make up air is passed to maintain that known pressure in that sealed cylinder.
typically a certain amount of leakage will be seen on the ring end gaps.
anything more than 15% (10% on a two stroke) is bad ju ju.Comment
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tHANK YOU FOR YOUR HELPComment
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