This repair and service manual covers Johnson outboard engines (all models) 3.5-250 HP, 2- and 4-stroke, 2002-2007.
Step-by-step illustrated keyed procedures guide you through every conceivable job possible, including all adjustments necessary. Perfect for do-it-yourselfers, professional mechanics, or students.
Book Excerpt: 2002-2007 Johnson Outboards Repair Manual 3.5-250 HP, 2-Stroke, 4-Stroke Models
LUBRICATION AND COOLING
OIL METERING SYSTEM (OMS) - 2-STROKE MOTORS
Unlike 4-stroke engines, which contain a reservoir of oil that is recirculated during engine operation, mixing oil with the fuel lubricates 2-stroke engines. Internal engine components of 2-stroke motors are lubricated as the fuel/oil mixture passes through the crankcase and the cylinder.
Generally speaking, there are 2 methods of adding oil to a 2-stroke outboard. The first is to pre-mix oil with the gasoline whenever the fuel tank is filled. The pre-mix method is generally used on smaller (lower horsepower) motors and on most commercial outboards. It is easiest to perform this on portable fuel tanks that can be agitated to ensure proper mixture, but it can be successfully accomplished on larger built-in tanks, as long as care is taken to properly measure the amounts of fuel/oil being added.
See Figure 57
Almost every marine engine around today requires at least one special tool to perform a certain task. In most cases, these tools are specially designed to overcome some unique problem or to fit some oddly sized component.
When manufacturers go through the trouble of making a special tool, it is usually necessary to use it to ensure that the job will be done right. A special tool might be designed to make a job easier, or it might be used to keep you from damaging or breaking a part.
Don't worry, MOST maintenance procedures can either be performed without any special tools OR, because the tools must be used for such basic things, they are commonly available for a reasonable price. It is usually just the low production, highly specialized tools (like a super thin 7-point star-shaped socket capable of 150 ft. lbs. (203 Nm) of torque that is used only on the crankshaft nut of the limited production what-dya-callit engine) that tend to be outrageously expensive and hard to find. Hopefully, you will probably never need such a tool.
Subject: 2002, 2003, 2004, 2005, 2006, 2007 Johnson Outboard 3.5-250 HP, 2-Stroke, 4-Stroke Models service, maintenance, repair. ISBN-10: 0893300721 | ISBN-13: 9780893300722 | Seloc 1314