1993 Yamaha 115Hp 2Stroke Water Pump Service

[roosterman]

Service on 1993 Yamaha 115 V4 water pump

Hi Guys,

Before i go on i would like to say i am not a marine mechanic just a handy guy who can do this sort of stuff and save a few $$ thats better spent on gear... always consult an expert as this is just a guide to show how easy things are to do yourself...

The reason i did this is because i noticed a loss of water pressure while flushing my motor so it is a good idea to get an idea of whats normal out of your tell tale (if ya have one) and if its slower you need to investigate if its a simple blockage or something a little more sinister..

Step 1.check gear lever is in neutral then you need to drain the oil out of the gearbox by putting a clean container under the bottom drainhole. remove bottom plug and check the magnet on end for metal filings etc,this is not good & if there is a bit there it will need further inspection of gears etc .remove top plug and oil should flow out of bottom hole,put fingers in oil coming out and rub together checking for gritty stuff,again not something you want to find...Oil should have a good color to it ,mine is golden color so all good.. not smell burnt or be cloudy or milky (a water contamination issue).

Step 2 .removing the box on this is easy as there is no linkage crap like Johnson/evinrude or some others as this uses a spline system to link box to leg. Undo speedo tube at front of motor

,then remove rubber cap above trim tab and remove bolt holding trim tab on.under the trim tab is a hidden bolt that is easily missed

and then 3 bolts eeach side holding box to leg..be carefull as once removed it may slide down but more than likely need a little pull.gently lower box keeping it straight so not to damage bushes/bearings up leg.

Step 3. Put box in vice with protective wood chocks or secure so its able to be upright and not fall. Pull the prop off by removing cotter pin with pliers/side cutters and remove castellated nut and thrust washer.pull prop off check spline shaft and inner prop hub for wear clean and wrap rag around shaft.

Step4. There is 4 bolts holding water pump housing to box,remove these and the washers and put in a clean container.lift housing off,this may need a little help.if the inner pump cartridge did not come off then pull this off .the impeller should now be there with a locking cap and washer above.gently pry the metal locking hub off the plastic sleave and remove both and the 3 washers sitting on the impeller.note that the middle washer is a spring type.the impeller is ready to pull off,there is a woodruff key that the imperrer slides onto that needs removing if you want to do oil seals under base plate but if alls good no need to go further(worth checking in my opinion)

[roosterman]

continued on

Step5 check base plate for grooving and wear marks and clean all mating surfaces of box etc.clean and check both inner/outer housings for wear or damage and look at impellor for cracks excessive bending etc that could be sign of no water pressure if that was reason for doing this,if alls good further look at thermostats and water galleries on block may be needed.lightly oil shaft and slide new impeller on,do not use old one as the $40 - $50 impeller price is not worth the risk.put 3 washers back on noting middle one is spring type then refit cleaned plastic sleave and metal locking hub.check and clean the outlet spout rubber and plastic seal for wear and replace if needed.fit new O ring lightly greased to inside base of outer hub then put sealant on top and outer of inner housing and fit this into outer housing making sure O ring stays put and no excess sealant gets in way of water flow area.fit new O ring lightly greased around lip of where 2 housings are in grove.to get this to fit over the impeller blades a trick is to get cable ties and wrap around blades making sure they bend the way yr motor needs,standard rotation is clockwise so blades bend anti clockwise or right ways.lightly oil base plate,blade edges and inner hub.slide hub assembly down carefully rotate shaft getting the first bits into hub then cut cable ties and push hub all way down onto locating pins making sure its facing right way.coat the 4 bolt threads with loctite 242 threadlock fit and tighten them to correct torque.

[roosterman]

and again...

Step 6 get all yr clean bolts for fitting box to the leg and coat thread with loctight thread locker.lightly grease drive shaft and splines of gear shift and main drive being very carefull to keep top clean otherwise hydraulic lock can occur when fitting. Carefully slide shaft back up leg guide speed tube up into position and also the water tube onto pump.fit longest bolt up through the missing trim tab(hidden bolt)and tighten loosly,fit 6 other box bolts loose at first then sequentially tighten them to correct torque. Fit trim tab and replace rubber cap.

Step 7 fit new washers to oil plugs,insert oil through bottom hole till it comes out top one,do not do this from top as it gets air lock and wont fill correctly.put top screw in then fit bottom one which has magnet on end(very important).

Step 8 put engine in tank or muffs and run for min of 5 min but preferably 10 to 15min keeping a good eye on tell tale/temp gauge.if not enough water pressure or temps too high kill motor and investigate thermostats etc for problems..

If all went well it should of taken about 2 beers or 30 – 60 minutes..

I also removed and cleaned the 2 thermostats and checked the operational temp(stamped on it 50c) again this was easy on my motor ,about ten mins all up but some are harder to get at.

Sometimes corrosion/stuck bolts/parts/ability etc mean its harder but not impossable for the home handyman to do simple routine maintenance like this,save some $ and get satisfaction from your pride and joy..

Once again this is only what ive done and is to outline the ease of doing it and to help others if they were not sure if they could do it themselves.

Motors do differ and some like older johnsons can be a pain so get a manuel to guide you and give it a go.

Cheers....steve........

[maz12]

You make the instructions so clear that even a layman could do it.

I HAVE A SUZUKI AND HOPEFULLY SOMEONE WILL POST A SIMILAR ARTICLE.

Well done.