Squealing 90hp Merc

[Bob Padgett]

" Dealer changed the impeller

" Dealer changed the impeller on my 97 Mercury 90hp ELPTO six months ago. Ever since, the motor makes a high pitched squealing noise for 1-2 minutes after running WOT for 5-10 minutes. The noise occurs in gear or idling in neutral. I've put about 25 hrs on the OB since the problem began. Pee stream is OK and no alarms sound, no bad symptoms except the noise - which is irritating me and probably scaring the fish! I've seen posts on other sites on the same problem, but they got no helpful advice. Can anybody help? "

 

[joereeves]

"Bob.... Mercurys are not my l

"Bob.... Mercurys are not my line of erpertise, but this is a problem that some Evinrude & Johnson owners complained about quite a number of years ago, and the squealing noise always came into being after a water pump was installed, or after a lower unit repair.

OMC came out with a bulletin that stated that the problem was caused by too much grease being applied on the top driveshaft splines when reinstalling the lower unit, creating a hydraulic action which fought against the natural up/down action of the driveshaft (the slight play needed to avoid friction etc).

OMC's remedy was to remove the lower unit, remove all of the present grease from the driveshaft, then reapply grease to all the splines EXCEPT ONE GROOVE. This allowed whatever excessive grease that might exist to travel down the clean goove when the unit was reinstalled.

This may or may not be your problem, but OMC's remedy cured the problem on their outboards. Let us know what happens.

Joe

"

 

[Bob Padgett]

" Thanks Joe, appreciate your

" Thanks Joe, appreciate your experience and help, and will check it out. "