Performing the scheduled maintenance is very important. When the tappets are set to the specified clearance, the engine will run without excessive noise from the valve mechanism and will deliver full power. If out of specification, adjust tappet clearance by changing shim. The tappet clearance specification is the same for both intake and exhaust valves. Adjust to within specified range if gap is out of specification. Keep Your Outboard Running Smoothly. The Yamaha outboard motor service manual downloads for the above listed models describes the service procedures for the complete engine.
Install compression gauge hose attachment into plug hole, then connect compression gauge hose to gauge hose attachment and compression gauge. Turning air screw clockwise : Engine speed will decrease. Remove propeller shaft seals if not removed with bearing in Step 9 and bearing carrier O-ring. Lift reverse gear, thrust bearing and thrust washer from bearing carrier. Start engine and allow to warm up as follows : Summer : 5 min. Two tappets can be adjusted at the same time 5.
However, enough information in 25 hp outboard repair manuals is given for do-it-yourself or apprentice mechanics to correctly and safely perform repair work to their 25 hp outboard motor and components. Close warm-up lever and then recheck engine speed. Start engine and allow it to run for several minutes at idle speed. Prop shaft trueness should be measured with a dial indicator with prop shaft on V-blocks. From 25 horsepower maintenance procedures to complete 25 horsepower outboard engine overhaul, these 25 horsepower manual covers it all. Lift impeller, drive key, and gasket from drive shaft.
Compression gauge Compression gauge hose Compression gauge hose attachment 5. Replace cam follower if worn or pitted. Start engine and allow to warm up. Battery solution gravity : 1. If bearing surface is damaged, replace drive shaft and corresponding bearing. Install special tool with camshaft housing bolts as shown in figure. Too small a tappet clearance may reduce engine power, too large a tappet clearance increases valve noise and hastens valve and seat wear.
Tighten engine oil drain plug to specified torque. Replace upper drive shaft bearing and sleeve if either are rust stained, or if bearing will not roll freely. The outboard marine mechanic should carefully read the text and become familiar with the 25 horsepower marine engine service manual procedures before beginning the work. Models Covered are Mercury - Mariner 9. From 25 hp maintenance procedures to complete 25 hp outboard engine overhaul, these 25 hp manual covers it all.
Some repair procedures in this 25 horsepower outboard downloadable manual may require the use of special tools. Replace propeller if splines are worn, damaged or twisted. Remove components from propeller shaft. Remove bearing from gear using Universal Puller Plate 91-37241 and mandrel. The subsequent pages give detailed procedures. Rotate crankshaft counterclockwise to bring cam nose vertical to shim surface. Remove engine oil drain plug and gasket to drain engine oil.
After removing shim, measure thickness of original shim and determine correct thickness of shim for proper tappet clearance as calculated by following formula. Connect negative — terminal second. Move and hold throttle lever in full-open position. From basic maintenance and troubleshooting to complete overhauls, our Yamaha Two-Stroke Outboard manuals provide the information you need. Remove oil level dipstick and wipe it clean. Apply constant pressure to cam follower in order to prevent it and internal components from ejecting out of the propeller shaft during removal of the cross pin from the clutch. If reverse gear must be replaced, pinion gear and sliding clutch should be inspected or damage.
Replace thrust bearing and thrust washer if rusted or damaged. Most all service manual chapters start with an assembly or system illustration, diagrams, exploded parts view, quality pictures, service information and troubleshooting for the section. With propeller shaft horizontal, pull carrier using tool shown to break seal with gear housing. If oil level is low, slowly inject gear oil up to the correct level. To perform fuel mixture check O2 feedback operation, use personal computer and Diagnostic System software.
Remove lower gear oil drain plug before gear oil level plug and drain gear oil. V6 3130cc 2-stroke 1994 1995 1996 225 hp 90 deg. Install oil level plug before removing oil filler tube from drain hole. Use suitable tools screwdriver and awl to remove retaining ring. Remove and discard rubber ring. Individuals using this 25 horsepower outboard marine repair manual should possess basic knowledge of tools and mechanical theory.