Main seal failire

[roverfj1200]

Hello all

Back again with this one. 120hp 2 piece box.Now had the problem before and have replaced the two upper bearings and had the shaft re machined. The seal in place is the right part number. some how the box would seem to pressurize and force the lower lip seal up trough the upper lip of the seal.

Now after the fix up I was away and used the motor for a week before the failure happened.


Any ideas no matter how unlikely???

Cheers.

 

[Frank Acampora]

Re: Main seal failire

Do you get water in the lower unit? Do you have ALL the O rings including the large one around the gearcase in place? Are the mating surfaces of the gearcase and mid unit sealing? If the mating surfaces are not good and are leaking impact water into the gearcase, you can not just machine them since they locate the pinion and set backlash. If you do machine these surfaces, you MUST re-shim the upper bearing to set pinion gear backlash. I believe it is .005 but measure twice FIRST before machining.

Is the lower plug in good and tight with a new plastic gasket?

Double check the water pump and plate. There should not be any water pressure against the seal but if incorrectly assembled, who knows? I did have that seal fail and pumped water into the lower unit. Ran a couple of hours with no oil, just water and luckily, she got me back to the dock before the gear pak was totally destroyed. Required replacing the whole lower unit though.

 

[roverfj1200]

Re: Main seal failire

thanks Frank. No the box is all sealed up well and was dry until the failure. Maybe there is a problem with the lower bearings or something. Have made a vent pipe that fits the oil level hole to relieve any pressure build up. Will use and hope this works OK until I can find a second hand box,,

Cheers..