2008 70 HP. knocking

[lilbubba]

I have a 2008 70 Yam. with 220 hours...The motor runs fine , accelerates fine, 5600 rpm wot , idles fine ...I normally keep it between 50-5300 RPM running...Today as I slowed down right before neutral I got a clicking noise a couple times sounding like the lower unit...The last time it did it was more like a knock or missfire in the head....I checked the lower unit oil and it looks the same as when I changed it last year which I change every year ...Everything seams to be tight propshaft wise and no loose parts on the engine....Any Ideas?????

 

[robert graham]

I'd pull the spark plugs to check them for any unusual firing indications....

 

[lilbubba]

Spark plugs show normal firing...Motor performs like a motor with only 220 hrs. should...Only problem is a knocking or clacking of gear noise when decelerating when it almost idles down...Bad part is it doesn't do it all the time....

 

[robert graham]

Some stainless steel props can cause knocking sounds at certain RPM's....Some motors have spring washers/collars just above the water pump to remove up and down movement/noise at certain RPM's.....has your water pump been replaced lately or ever?....

 

[lilbubba]

Water pump was replaced at appx. 175 hours....

 

[robert graham]

Might want to drop lower unit and check if your motor has this collar....if so, pull up on driveshaft while tapping collar down to remove slack/up or down movement from driveshaft.....