When installing the injector on the blower, tighten the bolts evenly to prevent
distortion. A gasket or silicone seal must be used between the injector and the
Nitro Type Metering Valve
The idle check valve should be installed where the housing is marked "RET". The
upper check valve is the high pressure pump relief and should also have a return
line. The fuel line from the pump should be connected to the fitting marked
"IN". The line to the port nozzles should be connected to the fitting marked
Methanol Type Metering Valve
The idle check valve should be installed where the block is marked "OUT".
Connect the return line to this check valve. The fuel line from the pump should
be connected to the fitting marked "IN". The fitting in the rear corner of the
metering valve should be connected to the top nozzle distribution block. Systems
utilizing port nozzles will have an outlet fitting installed in the bottom of
the metering valve.
The idle mixture is controlled by the turnbuckle on the side of the injector. To
richen the idle, rotate the turnbuckle towards the rear of the injector,
(shortening the linkage leans the mixture, lengthening richens the mixture).
This adjustment is for idle and throttle response only and has no effect on full
throttle. The idle speed is controlled by the butterfly shaft stops on each side
of the injector.
Main Bypass Jet
Each fuel injector is furnished with a set of bypass pills. This bypass controls
the fuel mixture at full throttle and has little or no effect on the idle. The
bypass pill is located under the 9/16 hex plug on the metering valve. Use a
smaller bypass to richen the fuel mixture and a larger bypass to lean it. When
installing the bypass, make sure that it is seated at the bottom of the threads.
High Speed Bypass System
Certain applications require the use of a hi-speed lean out. This consists of a
bypass pill controlled by a high pressure check valve which leans the fuel
mixture at high RPM. The check valve pressure is adjusted with shims to tailor
the fuel curve to the engine’s requirements. The check valve opens when the fuel
pressure is able to overcome the spring tension. The bypass pill controls the
volume of fuel returned. Adding shims will make the check valve open at a higher
RPM. Removing shims will make the check valve open at a lower RPM. The hi-speed
should be thought of as a fine tuning device. The main bypass pill is the
primary control of the overall fuel mixture.
The fuel system should be drained between races. It is important to lubricate
the fuel pump with LPS-3, WD-40, light oil or some other type of lubricant.
Remove the inlet line from the metering valve and lubricate the metering piston
to prevent stickiness and drying out.
You must use a 3-way fuel shutoff with a return to the fuel tank. A 2-way style
shutoff will damage the fuel pump.