0281420 JOHNSON MOTOR COVER ASSEMBLY, Evinrude

Using Fuel Consumption For Calculating the Overhaul Intervals
Experience has shown that maintenance intervals are most accurately based on fuel consumption. Fuel consumption corresponds more accurately to the engine load. Tables 1 and 2 list average ranges of fuel consumption and service hours for high displacement engines. These tables are based on a load factor of approximately 60 percent.High Displacement Engines
Table 1
Service Hours and Fuel Consumption for 3512B High Displacement Engines (1)    
Interval     Rated Up to 1300 RPM     Rated 1301 to 1600 RPM     Rated 1601 to 1800 RPM    
Top End Overhaul     11000 Service Hours     9000 Service Hours     7500 Service Hours    
1500000 L (395000 US gal) of fuel
Major Overhaul     22000 Service Hours     18000 Service Hours     15000 Service Hours    
3000000 L (790000 US gal) of fuel
( 1 ) Fuel consumption is based on a load factor of approximately 60 percent.
Table 2
Service Hours and Fuel Consumption for 3516B High Displacement Engines (1)    
Interval     Rated Up to 1300 RPM     Rated 1301 to 1600 RPM     Rated 1601 to 1800 RPM    
Top End Overhaul     11000 Service Hours     9000 Service Hours     7500 Service Hours    
2000000 L (528000 US gal) of fuel
Major Overhaul     22000 Service Hours     18000 Service Hours     15000 Service Hours    
4000000 L (1056000 US gal) of fuel
( 1 ) Fuel consumption is based on a load factor of approximately 60 percent.Use the actual records of fuel consumption, when possible. If the actual records are not available, use the following procedure in order to estimate the fuel consumption.
Estimate the average percent of the load for the operation of the engine.
Refer to the fuel consumption data in the Technical Marketing Information (TMI) for your engine. This will determine the fuel consumption for the percent of the load that was estimated in Step 1. Use this figure as variable "F" for the equation in Table 3. For more information about the Technical Marketing Information (TMI) for your engine, consult your Caterpillar dealer.
Table 3
Equation For Calculating Overhaul Intervals    
F/R = H    
"F" is the estimated total amount of fuel consumption of the engine.    
"R" is the rate of fuel consumption in liters per hour or gallons per hour.    
"H" is the number of estimated hours until the overhaul interval.    Oil Consumption as an Overhaul Indicator
Oil consumption, fuel consumption, and maintenance information can be used to estimate the total operating cost for your Caterpillar engine. Oil consumption can also be used to estimate the required capacity of a makeup oil tank that is suitable for the maintenance intervals.Oil consumption is in proportion to the percentage of the rated engine load. As the percentage of the engine load is increased, the amount of oil that is consumed per hour also increases.The oil consumption rate (brake specific oil consumption) is measured in grams per kW/h (lb per bhp). The brake specific oil consumption (BSOC) depends on the engine load. Consult your Caterpillar dealer for assistance in determining the typical oil consumption rate for your engine.When an engine's oil consumption has risen to three times the original oil consumption rate due to normal wear, an engine overhaul should be scheduled. There may be a corresponding increase in blowby and a slight increase in fuel consumption.