Installing a vacuum gage in your fuel delivery
system is a worth while option and will pay for itself quickly when its function
is understood by the boat operator.
Restriction or "Fuel Pressure Drop" across a filter is a function of fuel flow
vs. restriction or "clogging" of the filter. A well designed fuel filter system,
which includes all the types of fittings, hoses, valves, and "other things"
incorporated into the finished system, should start out CLEAN under 3" of Hg
restriction, when measured in-between the lift pump and the last "off engine
filter". We typically mount the gage on or after the last filter in the primary
Multi-Stage system because of convenience, and the fact that we do not consider
the fuel line and fittings (if properly sized) between the last filter and
the lift pump to be of any consequence in the overall restriction of the system.
My field work over the past 20 years has shown that "most"
diesels with properly operating lift pumps and fuel systems can tolerate about
10"-15" of mercury (Hg) restriction before starving for fuel... Again, always
put your vacuum gauge after your "off engine" fuel filters, but before any
pumps. And in actual operation, you will find that a good Multi-Stage system
will clog 2-3 primaries (FF5013) before the FS 1000 needs replacing - The vacuum
gage will tell to that as that is what multi-stage is all about. |
