This is an in-depth inspection of a vessel's drive system.
A mechanical survey can be performed on diesel or gasoline engines and on inboards, inboard/outboard, or outboards.
Control operation is verified: shifting, throttle, engine stop, neutral-start interlock, neutral detent, excess play or friction in controls, etc.
Engine raw water pump: flow is verified
Mechanical Inspection Survey
Tach operation is verified with hand-held digital tach, idle rpm is verified, tach indicated v.s. actual readings are charted; volt or amp meter operation is verified with external Fluke tester; temp gauge accuracy is verified with hand-held infra-red gauge or infra-red camera; if oil pressure is suspect, a mechanical oil pressure gauge is attached.
Charging is verified -- both volts and amps, overheat is checked, noises are evaluated, mounting and alignment are evaluated.
Cranking speed is checked, noises are evaluated
Compression test on a gasoline engine the spark plugs are removed and the compression is measured, spark plugs are inspected for type, appearance and gap
Cylinder Isolation Test
Compression is not tested, instead each cylinder is disabled and the rpm drop is recorded
Operational: Starting hot and cold
exhaust smoke cold and under load; warmup; throttle acceptance; WOT rpm no-load (diesel); maximum rpm underway; inspection of block, head, exhaust manifold, and exhaust elbow for local overheat (blockage); oil pressure and coolant temperature checked under load
Oil Sample Analysis
Engine and transmission oil sample lab analysis can be performed for evidence of wear metals, fuel or coolant contamination, soot, debris, etc. While a one-time oil analysis isn't as useful as periodic sampling, it can find more advanced problems
NOTE: There may be circumstances that prevent launching the vessel or prohibit leaving the dock. In these cases, the above procedures have to be modified to fit the circumstances.