View Full Version : Squealing at slow speeds

tall_ andy
06-17-2005, 05:51 PM
I've got an 88' MC 190 that makes a squealing sound when I am running in gear but at idle speed. It seems to go away as soon as I give it some gas. I was thinking it may be the packing around the shaft, but wasn't sure. I have not adjusted the packing nut. It started making the sound at the very end of last season, I thought it may be the colder water, but the water temp is 72 now so thats not it.
Any suggestions

06-17-2005, 05:52 PM
Check to make sure your alternator belt is tight.

06-17-2005, 05:54 PM
My 197 and my friends X-7 both whine occasionally when you are in gear at idol speed then it will go away if you give more gas. I figured it was a normal sound.

06-17-2005, 07:40 PM
Mine too. I think my sound is coming from the raw water pump but could be mistaken. Goes away as soon as the RPMs go up.

06-29-2005, 11:56 AM
I just finished rebuilding my raw water pump for the same issue (squeaky). Ordered the parts from Skidim (make sure you call them - they will hook you up with all the little C-clips and such). Also, look up the Sherwood website - they have rebuild instructions right on the website.

06-29-2005, 03:58 PM
Had the EXACT same problem in my old boat (Not MC) - Merc V-6 I/O. It was the alternator belt. Just tightening it did not do the trick. It was old, stiff and shiny. A new belt immediately solved the problem.

06-30-2005, 12:42 PM
What interests me is the fact that it only squeals in-gear at idle as opposed to out of gear. I guess that maybe the RPM reduction that occures from putting the boat in-gear produces just the right frequency for the whine, but I'm also questioning your trans fluid. Has it been changed recently?

Have someone run the boat in gear while you open the engine box and isolate the noise location. At that point, let us know where it's coming from. If it is the stuffing box, an adjustment is simple, if it's the tranny a fluid change is easy, and hopefully it's not a pump.