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Water Pump Replacement on a 25hp 1998 Merc. Mariner

S

stillense

New member
3 years ago I purchased a 14' Lund with a 25hp 1998 Merc. Mariner 2 stroke w/ tiller. I wanted to know how involved it would be to replace the water pump/impeller. I do not know when it was replaced and have read that it is good to replace every 2 years.I have limited boat experience but was able to winterize and replace lower unit oil last year without breaking the motor. thoughts/resources?
 
hi changing the impeller is not difficult check you tube loads of videos.you drop lower unit usually about 5 bolts. 1 may be hidden up under the trim tab so needs to come off. then a few bolts removes the pump housing the impeller just pulls up shaft and off but watch for the small piece of metal this must be put back on with new impeller a small amount of grease will hold it in place and you will see a groove at bottom of shaft where this sits. put very small amount of grease inside housing and as you put housing back on top of new impeller twist shaft clockwise and apply little pressure housing will slip back on replace bolts but take care and make sure housing is not touching shaft when you tighten bolts its really simple as i say videos on youtube very informative its not a hard job
 
I have always been advised not to use grease as,unlike washing liquid and petroleum jelly,it is not miscible with water and thickens into a paste,impeller vanes will stick and break.But then,doctors differ patients die:D
 
too true. i suppose all can do the job i just know ive always used a finger tip of grease and i have had no problems with using it. the idea is to let the impeller have a bit of slip till the water gets up to it as we all know no water soon no impeller
 
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