Servicing Yamaha’s Super Sniffer

the F-charred in last 100 hours, to be made using the … Yamaha Test Workshop (Exhibit No. YB-06767) between the connections …. Stale or contaminated fuel and oil only meet the minimum TC-W3 specifications ….

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Servicing Yamaha\’s Super Sniffer
When a Yamaha EFI engine is ailing, servicing the oxygen-density sensor may make it run more efficiently
The engine\’s Electronic Control Unit (ECU) adjusts the fuel injectors on time to compensate for any changes in the exhaust mixture FUEL INJECTION 101
Because the fuel pressure in the system is regulated to a constant amount (about 35 psi), opening the injector (on-off valve) for a short period of time (measured in thousandths of a second) allows a specific volume of gasoline to flow out of it. The O2 sensor determines if the engine is running too rich or too lean by sampling the amount of unburned oxygen in the exhaust gas and sends that information to the ECU.
The oxygen sensor is mounted behind the black plastic cover on the upper starboard side of the engine block at the No.1 cylinder. breathe air that contains about 21 percent oxygen. A rich mixture has less oxygen – a large distinction between exhaust and ambient air -and thus produces a higher output voltage. For an oxygen sensor to function correctly, it needs to be kept at or above 600 degrees.
Drivability issues can be the result of a number of engine- or boat-related problems that have to be resolved before condemning the oxygen sensor.
Remove the front air-silencer cover and run the engine until it comes up to temperature, at least 120 degrees, before conducting the test. The voltage shown on the meter screen will read between 0.3 and 0.6 volts DC with a good sensor and will vary continuously as the computer (ECU) adjusts the mixture.

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