Ran engine without lower unit lube.... Time to replace bearings ??

lemans

Cadet
Joined
Jun 6, 2012
Messages
17
Was testing engine today on 1984 Starcraft Islander, Mercruiser 140 I/O. Ran engine in driveway with cooling muffs on for about 15 minutes. Did not put drive into gear at all.
and did not go over about 1500 RPMs.

Outdrive made slight noise while being (trim) raised for about 3 seconds. Then realized that I had not filled lower unit with 90 weight gear oil. Shut down. Filled with lube, ran again for a few minutes, raised outdrive... no sound this time. Everything seemed fine.... but I question whether I burned up the tapered roller bearings. Not sure how I would inspect these, or how I would know if they had failed.
Comments .....?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
Was testing engine today on 1984 Starcraft Islander, Mercruiser 140 I/O. Ran engine in driveway with cooling muffs on for about 15 minutes. Did not put drive into gear at all.
and did not go over about 1500 RPMs.

Outdrive made slight noise while being (trim) raised for about 3 seconds. Then realized that I had not filled lower unit with 90 weight gear oil. Shut down. Filled with lube, ran again for a few minutes, raised outdrive... no sound this time. Everything seemed fine.... but I question whether I burned up the tapered roller bearings. Not sure how I would inspect these, or how I would know if they had failed.
Comments .....?

I think I would pull the top cap off the drive and see if you see any scoring, or material. Could also run it for a while, let it sit over night then pull bottom plug and see if there is anything that comes out that gives you concern.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Was testing engine today on 1984 Starcraft Islander, Mercruiser 140 I/O. Ran engine in driveway with cooling muffs on for about 15 minutes. Did not put drive into gear at all.
and did not go over about 1500 RPMs.

Outdrive made slight noise while being (trim) raised for about 3 seconds. Then realized that I had not filled lower unit with 90 weight gear oil. Shut down. Filled with lube, ran again for a few minutes, raised outdrive... no sound this time. Everything seemed fine.... but I question whether I burned up the tapered roller bearings. Not sure how I would inspect these, or how I would know if they had failed.
Comments .....?

You ran a drive that had residual oil in it UNLOADED for about 15 min?

You likely didn't hurt a thing!

Just fill it up with oil and go boating.
 

lemans

Cadet
Joined
Jun 6, 2012
Messages
17
I inspected, filled lower unit and ran the Starcraft on the water, no problems or issues.... thanks for the responses !
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
The only thing you might want to do is change the lube before you normally would since I may have picked up a little bit more wear than normal.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
On muffs is without load. No harm no foul. Fill with oil and enjoy.
 
Top