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MARINE TECHNICIANTODAY | SPRING 2015
Eventually, due to age or a dose of dirty
fuel, the injectors may become restricted.
There are small basket filters that filter the fuel as the
fuel enters the injector. These filters can become restricted
by dirty fuel, can dry rot, crack, break apart and clog or affect the
spray pattern of the injector. Dirty fuel can bypass a deteriorated basket
filter further reducing the performance of the injector. Many technicians
attempt to do their own fuel injector cleaning; this is a big mistake as they
don’t have the proper equipment nor the knowledge to do so. Not only
do the injectors need to be cleaned, but they need to be flow tested to
confirm proper operation. Without the proper equipment this can’t be done
successfully. Flow testing injectors requires a testing fluid that flows like
gasoline and has the same overall average specific gravity of gasoline. Many
cleaning services use mineral spirits as the flow testing fluid as it is cheap
to purchase and readily available. This is a poor choice in fluids for flow
testing as its specific gravity is not the same as gasoline and often gives
improper results. The fluid chosen must be tested to verify that its specific
gravity is close to that of gasoline. During injector operation, and during the
cleaning process, the injectors are pulsed on and off. This is called “duty
cycle.” They are only activated for a specific amount of milliseconds during
an injection event. Never apply 12VDC to the terminals of an injector to
activate it! Doing this will instantly and permanently damage it. The solenoid
windings will overheat and melt the wire’s enamel coating or the wires
themselves resulting in an open or shorted injector.
There are many professional cleaning machines available. In the next article
I will discuss the pitfalls of some, and how to pick a good provider for your
cleaning and service needs. Also I will discuss the specific details of injector
flow testing and cleaning. Some services fall short because the testing and
cleaning is only as good as the person operating the fuel injector flow testing
and cleaning machine.
Thanks for reading. If you have any questions about fuel injector testing,
flowing and cleaning fuel injectors or looking for a service provider, feel
free to call Boats Unlimited Performance at 817-658-7721 or email:
For more information about marine engine development contact Bob Madara,
Marine Kinetics 114 Woodrow Ave. Rochester, NY 14609. Phone 585-654-8583
email
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Common top feed fuel injector
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Multi Port fuel injection with 8 fuel injectors
