As airplanes and engines attain age, there appears to be a need to reemphasize the inspection or replacement of engine hoses or lines carrying fuel, oil or hydraulic fluid. The hose manufacturers definitely recommend regular inspection and replacement of all such hoses at engine overhaul even though they look good. Age limit of rubber-steel or fiber-banded hose has generally been established at...

Little things are sometimes forgotten so a reminder is sometimes necessary. In the case of the Lycoming O-235 engine, it is a little different from most other Lycoming models. Other models are equipped with hydraulic tappets which do not require frequent adjustment. Occasionally, there is a report of an O-235 which is running rough or not producing normal power. Investigation often reveals that...

It’s important to constantly stress the correct cylinder base nut tightening procedure. Operators in the field are occasionally having engine problems and malfunctioning after reinstalling cylinders, and not tightening the cylinder base nuts correctly. The latter tends to cause crankshaft bearing shifting, crankcase fretting or broken cylinder studs, and possible engine failure. Maintenance people...

Reports from operators of fuel-injected engines and from Lycoming service representatives provide some insights into the subject of clogged fuel-injector nozzles. Providing our readers with information from these sources may help some of them recognize and treat a similar problem in their own aircraft. A letter from the owner of a twin-engine aircraft with Lycoming IO- 540 engines indicated that...

The latest revision of Lycoming Service Instruction No. 1012 provides information on the location and assembly procedure for counterweights on each Lycoming crankshaft equipped with counterweights. The illustrations and engine listing in this service instruction show that some crankshafts may have two or more counterweights of the same part number attached to the crankshaft with rollers having...

In an attempt to reduce the cost of flying, some operators have resorted to methods of operation which are considered to be unsafe. Lycoming makes the following recommendations regarding these practices: Do not advance timing – set timing in accordance with the Engine Operator’s Manual for the specific engine model. Do not use a hotter spark plug for low-power cruise – unless it is approved for...

Damage to an aircraft that has been struck by lightning is often confined to a specific area of the structure. In such instances where the engine and its accessories, controls, fuel or exhaust systems are involved, it is necessary to evaluate and repair the damage before the aircraft is flown again. Although the path of the lightning may appear to have been around the external housings of the...