881351 1 Mercury SCREW

Illustration 1 g00745964
(Y) Cost
(X) Time
(1) Cost of maintenance and repair that is planned
(2) Cost of maintenance and repair that is not plannedIn Illustration 1, line (1) represents the maintenance and repair costs for an owner that followed the recommendations for inspection, maintenance, and repair. The peaks represent overhauls.Line (2) represents the maintenance and repair costs for an owner that chose to operate beyond the recommended intervals. The initial cost of the “repair-after-failure” philosophy is lower. Also, the first overhaul was delayed. However, the peaks are higher than the peaks for the customer that used the “repair-before-failure” philosophy .The higher peaks result from two key factors:
Delaying an overhaul until a breakdown increases the chance of a catastrophic failure. This type of failure requires more parts, labor, and cleanup.
Excessive wear means that fewer components will be reusable. More labor may be required for salvage or repair of the components.When all the costs are considered, “repair-before-failure” is the least expensive alternative for most components and engines.Waiting until the engine exhibits symptoms of excessive wear or failure is not practical. Waiting is not less costly. A planned overhaul before failure may be the best value for the following reasons:
Costly unplanned downtime can be avoided.
Many original parts can be reused according to the guidelines for reusable parts.
The service life of the engine can be extended without the risk of a major catastrophe due to engine failure.
Achieve the best cost/value relationship per hour of extended service life.Overhaul Inspection
Refer to the Service Manual for the disassembly and assembly procedures that are necessary to perform the required maintenance on the items that are listed. Consult your Cat dealer for assistance.To determine the reusability publications that are needed to inspect the engine, refer to Guidelines for Reusable Parts and Salvage Operations, SEBF8029, "Index of Publications on Reusability or Salvage of Used Parts".The Guidelines For Reusable Parts and Salvage Operations is part of an established Cat parts reusability program. These guidelines were developed to assist Cat dealers and customers reduce costs by avoiding unnecessary expenditures for new parts. If the engine parts comply with the established inspection specifications, the parts can be reused.The use of out-of-spec parts could result in unscheduled downtime and/or costly repairs. The use of out-of-spec parts can also contribute to increased fuel consumption and reduction of engine efficiency. New parts are not necessary if the old parts can be reused, repaired, or salvaged. Otherwise, the old parts can be replaced or exchanged.Your Cat dealer can provide the parts that are needed to rebuild the engine at the least possible cost.Overhaul Programs
An economical way to obtain most of the parts that are needed for overhauls is to use Cat remanufactured parts. Cat remanufactured parts are available at a fraction of the cost of new parts. These parts have been rebuilt by Caterpillar and certified for use. The following components are examples of the remanufactured parts:
Cylinder heads
Oil Pumps
Turbochargers
Water pumpsConsult your Cat dealer for details and for a list of the remanufactured parts that are available.Your Cat dealer may be offering various overhaul options.A Flat Rate Overhaul guarantees the maximum price that you will pay for an overhaul. Flat rate prices on preventive maintenance programs or major repair options are available from many servicing dealers for all Cat Engines. Consult your Cat dealer to schedule a before failure overhaul.Overhaul Recommendation
Caterpillar recommends a scheduled overhaul to minimize downtime. A scheduled overhaul will provide the lowest cost and the greatest value. Schedule an overhaul with your Cat dealer.Overhaul programs vary between dealers. To obtain specific information about the types of overhaul programs and services, consult your Cat dealer.Overhaul Intervals
Some factors that are important for determining the overhaul intervals include the following considerations:
Performance of preventive maintenance
Use of recommended lubricants
Use of recommended coolants
Use of recommended fuels
Proper installation
Operating conditions
Operation within acceptable limits
Engine load
Engine speedGenerally, engines that are operated at a reduced load and/or speed achieve more service life before an overhaul. This statement is for engines that are properly operated and maintained.Other factors must also be considered for determining a major overhaul:
The total amount of fuel consumption
The service hours of the engine
An increase of oil consumption
An increase of crankcase blowby
The wear metal analysis of the lube oil
An increase in the levels of noise and vibrationAn increase of wear metals in the lube oil indicates that the bearings and the wear surfaces may require service. An increase in the levels of noise and vibration indicates that rotating parts require service.Note: Oil analysis may indicate a decrease of wear metals in the lube oil. The cylinder liners may be worn so that polishing of the bore occurs. Also, the increased use of lube oil will dilute the wear metals.Monitor the engine as the engine accumulates service hours. Consult your Cat dealer about scheduling a major overhaul.Note: The driven equipment may also require service when the engine is overhauled. Refer to the literature that is provided by the OEM of the driven equipment.Use whichever criteria occurs first to determine the correct overhaul interval..
Table 1
Overhaul Maintenance Interval Schedule(1)(2)(3)
Interval Fuel Burned Service Hours(4) MW/hrs Maintenance Procedures
Top End 2200000 L (600000 US gal) 16000 10000 Refer to this Operation and Maintenance Manual, "Overhaul (Top End)".
In-chassis overhaul and general inspection 4400000 L (1200000 US gal) 32000 20000 Refer to this Operation and Maintenance Manual, "Overhaul (In-Frame)"
Major overhaul (out of chassis) 6600000 L (1800000 US gal) 48000 30000 Refer to this Operation and Maintenance Manual, "Overhaul (Major)"
(1) Engines rated at 1800 rpm
(2) Assumption based on cycle weighted fuel efficiency of 218
(3) Fuel burns, service hours, and MW/hrs start from the date of manufacture or remanufacture. Fuel burns, service hours, and MW/hrs are cumulative.
(4) Service hours are calculated based on 25% load factor and 566.6 L (149.7 US gal) per hour.Oil Consumption as an Overhaul Indicator
Oil consumption, fuel consumption, and maintenance information can be used to est