Hirth F-23, Operator'S Manual

Page: 19 / 34

19
CARBURETOR SETTING
With a pencil and pad, note type of carburetor and carb adjustment settings.
Refer to table of data and adjustments. These settings should be within
½ turn from that
which is shown in table.
Note: The carburetor jets shown in chart of data and adjustments shows what jets come as
standard equipment with the engine and which would be a good starting point for
adjustments and settings in most cases. In no way does this chart show what would be
optimum carburetor jetting or settings for the users particular operating conditions at locale.
It is the responsibility of the owner/operator to ensure that the carburetors are jetted and
adjusted properly.
It is possible that the engine will require carburetor jets that are other than those which are
supplied. It is a good idea to purchase an assortment of carburetor jets.
In most cases, the supplied jets should be sufficient to optimally tune the engine for summer
and winter operation and sea level to several thousand feet field elevation.
Although jet changes may be required, these changes should not be conducted unless proper
Hirth tuning information is on hand and the changes are made by a qualified person.
Hirth uses different brands of carburetors throughout its engine line.
For engine model F-23 the Mikuni VM34mm slide-type float carburetor is standard.
Optionally available are the Mikuni Super BN 34mm carbs. Jetting varies between engine
models and standard factory jetting for each model is listed on the engine settings page in this
manual.
A Mikuni carburetor manual is included with engine. You should read it before running
engine and become familiar with how your carburetor operates and its different components.
If your engine was supplied with fuel injection, you should have received a fuel injection
operator’s manual. Refer to the fuel injection manual for all
aspects of installation and
operation of the fuel system.