3C7-61341-1 Tohatsu MOUNT HOLDING PLATE UPPER

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. Table 1 lists average ranges of fuel consumption and service hours for a specific load factor.
Table 1
Interval Fuel Consumption(1) Service Hours
Major Overhaul 855000 L (226000 US gal) 4000
(1) Fuel consumption is based on a load factor of approximately 36 percent.Use the actual records of fuel consumption, when possible. If the actual records are not available, use the following procedure 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 information 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 2. For more information about the Technical Marketing Information (TMI) for your engine, consult your Cat dealer.
Table 2
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 Cat 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 (BSOC) is measured in grams per kW/h (lb per bhp). The BSOC depends on the engine load. Consult your Cat dealer for assistance in determining the typical oil consumption rate for your engine.When engine 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.Severe Operation
Severe operation is the use of an engine that exceeds current published standards for that engine. Caterpillar maintains standards for the following engine parameters:
Horsepower
Range of rpm
Fuel consumption
Fuel quality
Altitude
Maintenance intervals
Selection of oil
Selection of coolant
Environmental qualities
Installation
Average startsRefer to the standards for your engine or consult your Cat dealer to determine if your engine is operating within the defined parameters.Severe operation can accelerate component wear. Engines that are operating under severe conditions may need more frequent maintenance intervals for the following reasons:
Maximum reliabilityBecause of individual applications, identifying the factors which can contribute to severe operation can be difficult. Consult your Cat dealer about the maintenance that is needed for your specific engine.The following factors can contribute to severe operation: environment, improper operating procedures, and improper maintenance practices.Environmental Factors
Extreme Ambient Temperatures
Extended operation in environments that are cold or hot can damage components. Valve components can be damaged by carbon buildup if the engine is frequently started and stopped in cold temperatures. Hot inlet air reduces the performance capabilities of the engine.Note: See this Operation and Maintenance Manual, "Cold-Weather Operation" topic (Operation Section), or see Supplement, SEBU5898, "Cold-Weather Recommendations".Cleanliness
Unless the equipment is cleaned regularly, extended operation in a dirty environment and in a dusty environment can damage components. Built up mud, dirt, and dust can encase components. This buildup can make maintenance difficult. The buildup can contain corrosive chemicals. Corrosive chemicals and salt can damage some components.Improper Operating Procedures
Extended operation at low idle
Minimum cool down periods after high load factor operation
Operating the engine beyond the guidelines for the engine rating
Operating the engine at loads that are greater than the rated load
Operating the engine at speeds that are greater than the rated speed
Use of the engine for an application that is not approvedAverage Starts
Reducing engine idle time with a manual or automated strategy will increase the number of starts over the lifetime of an engine. Using a non-Caterpillar approved system to reduce idle time can result in higher engine component wear that is associated with severe operation. Some components that would be included are camshafts and bearings. Engines installed in pressure pumping applications typically average less than one start for every 4 hours of operation. Exceeding this average over the lifetime of the engine is considered severe operation.Cat engines equipped with Cat Engine Idle Reduction Systems are validated to reduce fuel costs associated with engine idle and to maintain Overhaul service intervals outlined in this Operation and Maintenance Manual for pressure pumping applications.Improper Maintenance Practices
Extension of maintenance intervals
Not using recommended fuel, lubricants, and coolant