1984 90 HP, 6 Cylinder Mercury outboard

[copley]

2 inch hairline crack in lower unit on top of propeller. Gear oil ok. Boat has been idle for several years. Low hours. Seems to run fine with muffs. Trim tab is missing. Is engine ok or is it scrap? Has anyone experienced this?

 

[emckelvy]

Re: 1984 90 HP, 6 Cylinder Mercury outboard

If it doesn't look like it's gone into the oil-containing part of the gearcase yet, you may be able to have someone MIG or TIG repair the crack to keep it from spreading.<br /><br />It may open up if you continue to run it as is, especially in salt water.<br /><br />If you do get it repaired, drain the gear oil out prior to welding, as the heat can cause a gearcase full of oil to be overpressurized and blow out the oil seals.<br /><br />HTH........ed

 

[achris]

Re: 1984 90 HP, 6 Cylinder Mercury outboard

This is a common problem with these gearcases. It's caused by corrosion building up under the rear end of the bearing carrier and locknut.<br /><br />You could just have it welded (heed Ed Mc warning) but it will open up again in time. The way to repair it completely is to remove the bearing carrier and clean all the corrosion out of the end of the gearcase, then have it welded. Reassemble with a good grease, like Merc Special lube 101 or Aqua-lube. <br /><br />Chris.............

 

[copley]

Re: 1984 90 HP, 6 Cylinder Mercury outboard

Thanks a lot. I'll give it a try. Can't lose. RayW

Originally posted by achris:<br /> This is a common problem with these gearcases. It's caused by corrosion building up under the rear end of the bearing carrier and locknut.<br /><br />You could just have it welded (heed Ed Mc warning) but it will open up again in time. The way to repair it completely is to remove the bearing carrier and clean all the corrosion out of the end of the gearcase, then have it welded. Reassemble with a good grease, like Merc Special lube 101 or Aqua-lube. <br /><br />Chris.............