noise in motor after impeller change

[mach1cj]

just had my impeller changed a couple weeks ago, (2006 Merc 115 4 stroke) and now its making a rather loud noise in neutral after warm up. motor was always very quiet. took it back and the mechanic dropped the lower unit and everything looked good. It's quiet when you first start it up, but after it warms up, the noise begins. It's only in neutral when you hear the noise, when you put it in gear, its dead quiet. The mechanic called Mercury and they had no ideas what could be causing the noise. The motor runs fine and the pee stream is strong. any ideas what it could be?

 

[Scott Danforth]

Check the gear lube

 

[enginepower]

He may have the lower unit out of synch. Slowly attempt to move it to forward or reverse gear and see if noise changes or goes away.

 

[mach1cj]

Check the gear lube

Scott, I did check and actually change the gear lube...it was clear as a bell.

 

[mach1cj]

He may have the lower unit out of synch. Slowly attempt to move it to forward or reverse gear and see if noise changes or goes away.

EP, the noise absolutely goes away when you put it in gear, either forward or reverse. it only makes the noise in neutral and only when the motor is warmed up.

 

[joed]

What he is asking is to move it slightly out of neutral and see if the noise goes away. I think he is suspecting that the control is out of sync the gears are actually not fully disengaging and are grinding on each other while in neutral.

 

[schematic]

not sure of your model, but if its a squealing noise, you may have a dry "steady bearing" on driveshaft

 

[mach1cj]

The mechanic greased the shaft about half way up where the bearing rides...noise doesn't sound like gears...its more like a medium whine.

 

[schematic]

serial number?

 

[mach1cj]

1B273054

 

[schematic]

is it possible he over greased the top of the driveshaft? (could cause severe end loading)

 

[mach1cj]

we checked that...the top had no grease, just the splines were greased. I have a video (sound) of the noise on my phone and the mechanic sent it to Mercury, but they couldn't explain it. something not right because it was always quiet before, barely knew it was running.

 

[schematic]

verify if the noise is coming from the gearcase. Use a stethoscope or a long screw driver with handle pressed against your ear.

 

[mach1cj]

Had the boat out the other day...still making noise in neutral. definitively coming from lower unit.

 

[enginepower]

If it's a clicking/ratcheting type noise and this happen after you changed impeller, you need to pull it back off and get the shifter back in right position before you tear your lower unit up.

 

[GOS]

just had my impeller changed a couple weeks ago, (2006 Merc 115 4 stroke) and now its making a rather loud noise in neutral after warm up. motor was always very quiet. took it back and the mechanic dropped the lower unit and everything looked good. It's quiet when you first start it up, but after it warms up, the noise begins. It's only in neutral when you hear the noise, when you put it in gear, its dead quiet. The mechanic called Mercury and they had no ideas what could be causing the noise. The motor runs fine and the pee stream is strong. any ideas what it could be?

 

[GOS]

Mach1CJ
were you ever able to figure out why you were hearing that whining sound in your 2006 Merc 115 while it was in Nuetral after changing out the impellor?
I have the exact same motor and am experiencing the exact same thing. put it into gear and sound goes away. Motor used to be so quiet in Neutral that sometimes I would forget to turn it off while fishing.
Thanks for any info you might have.