GENERAL INFORMATION 9 1 Tl IREAD LOCK Because of the marine engine's opera ting conditions, a threadlock (Figure 16) is required to help secure many of the fasteners. A threadlock will lock fasteners against vi- bration loosening and seal against leaks. Loctite 242 (blue) and 27 1 (red) are recommended for many threadlock requirements described in this manual. Loctite 242 (blue) is a medium-strength threadlock, and component disassembly can be performed with normal hand tools. Loctite 271(red) is a high-strength threadlock, and heat or special tools, such as a press or puller, arc re- quired for component disassembly. tions.
The lower the number, the easier the engine will turn over in cold climates. Higher numbers arc usually recommended for engine running in hot weather condi- t ions. Applying T hr eadlock Additional informat ion is provided in Chapter Four. Surfaces should be clean . If a threadlock was previ- ously applied to the component, this residue should also be removed. Gr ease Greases are graded by the National Lubricating Grease Institute (NLGT). Greases are graded by number accord- ing to the consistency of the grease; these range from No. 000 to No.6 , with No .6 being the most solid. A typical multipurpose grease is NLG I No .2 .
For specific applica- tions, equipment manufacturers may require grease with an additive such as molybdenum disulfide (MoS 2) . Shake the Loctite container thoroughly and apply to both parts. Assemble parts and/or tighten fasteners. BASIC llANO TOOL S Many of the procedures in this manual can accom- plished with simple hand tools and test equipment famil- iar to the average home mechanic. Keep tools clean and organized in a toolbox. After using a tool, wipe off dirt and grease and return the tool to its correct place. Wiping tools off is especially important if servicing the craft in ar- eas where they can come in contact with sand.
Sand is very abrasive and will cause premature wear to engine parts . High-quality tools are essential; they arc also more eco- nomica l in the long run. Stay away from the advertised specials featured at some stores. These are usually a poor grade tool that can be sold cheaply. They are usually made of inferior material and arc thick, heavy and clumsy. Their rough finish makes them difficult to clean , and they usu- ally don't last very long. Quality tools are made of alloy steel and arc heat treated for greater strength. They are lighter and better balanced than poorly made ones. Their surface is smooth, making them a pleasure to work with and easy to clean.
The initial cost of quality tools may be more, but they are less expen- sive in the long run. RTV G ASKET SEALA NT Room temperature vulcanizing (RTV) sealant is used on some pre-formed gaskets and to seal some compo- nents. RTV is a silicone gel supplied in tubes and can be purchased in a number of different colors. Moisture in the air causes RTV to cure. Always place the cap on the tube as soon as possible when using RTV RTV has a shelf life of one year and will not cure properly if the shelf life has expired . Check the expiration date on RTV tubes before usc, and keep partially used tubes tightly sealed. App lying RTV Sealant Clean all gasket residue and contaminants from mating surfaces.
Remove all RTV gasket material from blind at- taching holes, as it will affect bolt torque. Apply RTV sealant in a continuous bead 2-3 mm (0.08-0.12 in.) thick. Circle all mounting holes unless oth- en-vise specified. Torque mating parts within 10 minutes after application. The following tools are required to perform virtually any repair job. Each tool is described and the recom- mended sizes given. Metric size tools arc required to ser- vice Yanmar diesels. - - - - - - - - - - - - - - - --