No, the fuel indicating system on a Cessna 152 is unique and McFarlane has not designed a transmitter for them yet. However, we do have replacement fuel quantity transmitter gaskets and screw seal assemblies available for this aircraft.
Yes. The fuel screen is removed by removing the standpipe. The rubber tipped plunger must be unseated before the standpipe is loosened. Failure to lift the plunger off of its standpipe seat can damage the plunger. Pull the strainer drain knob as if you were draining the fuel bowl. Block or clamp the knob in this position. Insert a smooth round tool such as a screw driver or punch in the standpipe cross-hole and un-screw the standpipe.
Yes, please review the Installation Tips for McFarlane Fuel Vent Lines.
This motor is less susceptible to permanent magnet demagnetization at low and subzero temperatures, improving reliability in cold weather compared to the OEM.
The fuel selector valve works in unscreened fuel. Contaminated fuel can cause selector valve seal damage. When fueling from possibly contaminated fuel sources McFarlane recommends the use of a fuel filter, such as Mr. Funnel or another filtering device, to reduce trash in the fuel system.
The most common indication of external fuel valve leaks is the smell of avgas in the cabin. Most valves are located under the cabin floor. Fuel stain on the valve and drain plug or drain valve or on the belly of the aircraft can also indicate external leakage. External leaks are generally around the actuation valve stem. Internal leaks are detected when the fuel is turned off and fuel continues to drip during fuel system maintenance. Inner port leakage will allow fuel from one tank to leak into another fuel tank. This type leak is difficult to detect. Fuel transfer from one tank to another with the fuel valve selected to one tank only will indicate inner-port leakage. An extended period of time is needed to detect fuel transfer from one tank to another. Generally if internal leakage is detected when servicing the fuel system, it is likely there is also inner-port leakage.
Curtis Superior and SAF-AIR valves are designed for installation in a standard NPT port for NPT threaded valves or an AND-10050 style port for UNF threaded valves. Use a thread sealant or Teflon tape on pipe threaded valves. Never allow any thread sealant on the first thread . This will prevent contamination of the fuel system. Refer to aircraft manufacturer's torque specifications for the aircraft in which it is being used.
Replace the rubber seals as per the aircraft manufacturer’s recommendations or every ten years when no guidance is given. McFarlane stocks replacement seals and seal kits for both Curtis Superior and SAF-AIR valves. The new Curtis valves use a O-ring type seal instead of the flat seal that was previously used.
SAF-AIR valves are designed to be disassembled and the O-rings replaced. Over time, if the valve should start to leak, check to make sure the drain valve is tight. If drain valve is found to be tight, then check the O-rings. All O-rings used are buna "n", MS29513 Style, MIL-P-5315. SAF-AIR O-ring seal kits are available for most of their valves. Add a "K" or "-K" suffix to the valve part number.
Never have a hose attached in flight to the oil drain valve. Engine vibration and the additional attached mass can cause premature seal and valve wear which could result in valve failure and a loss of engine oil.
The McFarlane primer is available as a complete fuel primer assembly and knob assembly only, and replacement seals for the knob assembly are available. In many cases, where the old primer bore is still good, the McFarlane knob assembly can be used for a FAA-PMA approved quick fix for your existing primer.
A common cause for this problem is fuel starvation due to improper installation of the fuel pump. Make sure that the fuel lines are not crossed; that is, the inlet line should be connected to the inlet side of the pump (marked “IN” on the top of the port) and the outlet line should be attached to the fuel pump outlet port. Fuel should be present at the inlet side of the fuel pump.
Improper installation of the fuel pump may result in a misalignment of the operating lever with the operating plunger in the accessory case. If so, there will be no movement of the lever and no pumping motion to provide fuel flow. If misalignment is found upon removal of the pump, the lever is probably damaged or broken. If misalignment of the operating lever has occurred, it will require inspection and repair by a qualified technician.
There are several other components in the fuel indicating system which could be the issue or are causing the indication problems:
Caution! Never short the battery power to the transmitter wire! It will take only seconds before the stainless steel resistance wire in the Cessna transmitter will glow red hot in the fuel tank. The hot wire could explode the tank! Never have power on when trouble shooting the fuel gauging system.
Electricity in the Fuel Tank. Is it Safe?
Always check the fuel gauge system for proper calibration per the Cessna maintenance instructions.
Do you have aftermarket Monarch fuel tanks installed? We have received customer feedback stating that when Monarch or other aftermarket fuel tanks are installed, McFarlane’s fuel vent line does not fit. There is nothing we can do to solve that issue. McFarlane’s fuel vent lines fit well when OEM fuel tanks are installed. Please review the Installation Tips for McFarlane Fuel Vent Lines.
Diaphragm fuel pumps should be replaced or overhauled:
Yes, it provides a lower-cost alternative while offering improved reliability and performance in demanding conditions.
Yes, it is a direct replacement designed to match the form, fit, and function of the OEM motor. It installs in the same location and interfaces with existing flap system components without modification.
The Viton gasket and screw seals do not require any sealer and must not have any lubricants. Do not over tighten the attachment screws as over tightening can extrude the gasket out from under the transmitter and tear the gasket in the screw holes. This will cause a leak. Tighten the screws evenly until you see the gasket just start to extrude a little. Any lubrication will aggravate the tearing of the gasket.
This motor is FAA-PMA approved as a replacement for P/N C301002-0103 and fits a range of Cessna, Piper, and Beechcraft aircraft. Always confirm applicability using the PMA supplement or your aircraft’s IPC.
The most common reasons for low fuel flow/pressure are the following:
Fluctuating fuel pressure can be the result of the following:
Leaking fuel or oil through the fuel pump overboard drain line indicates the rotary seal is running dry or contamination happened in the field. Your fuel pump should be replaced before further flight.
Cessna SEB99-18R1 describes periodic checks of the fuel gauging system.
The varnish helps secure the windings against vibration, improves heat dissipation, and protects against moisture, dust, and debris. It also reduces the risk of electrical shorts and contributes to longer motor life.
The primary advantage is improved reliability, including reduced circuit breaker trips and better performance in cold environments, even with a slightly slower operating speed.
We pressure test our repaired valves to a minimum of 5 psi using precision controlled air pressure and a calibrated low pressure indicator. This pressure is above the normal fuel pressure on the valve and below the limits of the springs in the valve. Each valve is submerged in Stoddard solvent while the air pressure is applied to the valve. The valves are then tested in each position to assure that there are no inter-port or external leaks. Leaks are detected by looking for air bubbles escaping from the valve.
When replacing the flap motor, it’s a good time to inspect flap control cables, flap position indicator cables, and other flight control cables for wear or damage to ensure proper system performance
Over the years, there were some variations in the original vent lines from Cessna, and variations in the location of the exit hole in the wing. The vent line can be bent a little for proper fit. See the Installation Tips for McFarlane Fuel Vent Lines.
This motor is engineered to operate with more consistent electrical load characteristics, which reduces current spikes during operation. As a result, it has a lower tendency to trip the flap motor circuit breaker compared to the OEM.
The reduced speed helps improve reliability by lowering internal stress on components and reducing electrical demand. This makes the motor more dependable, especially in conditions where consistent operation is critical.
Yes, the motor operates at a slightly lower RPM than the OEM, which results in a modest increase in flap cycle time. This increase is minimal and does not affect safe aircraft operation.