lower crank seal on a 92 c85 hp

[scarab30/200]

what causes the lower crank seal to start leaking on a 1992 c85 tlrq Yamaha ? would it suck air and run lean causing power head failure ? noticed oil running down the front of the mid section. not clean oil , appears to be mixed fuel residue . this is not an oil injected engine . does the engine need to be dismantled to replace any seals or gaskets? split the case or what have you? thanks in advance for all info given mike

[scarab30/200]

anyone ? could use a little insight . thank you

[robert graham]

How is the motor running?....

[scarab30/200]

appears to be good except for the oil running down the front of the midsection

[robert graham]

appears to be good except for the oil running down the front of the midsection

My motor is a 1999 C90 and it has some oil in various places....yours may be a leaking or overflowing carburetor....do you tilt the motor up when not being used, causing some loss of fuel from carbs?....

[scarab30/200]

in the process of doing a break in is the reason for the questions. do not want to run lean and have to rebuild again. the only things that wasn't changed were the lower crank seals due to the fact they looked to be in good shape. thanks for any and all info provided

[rodbolt17]

wasn't a rebuild then.
but to answer,no nothing has to be split. you do have to remove the power head.

[ausnoelm]

Not knocking your rebuild procedure, but I can't imagine ever doing a rebuild and not replacing every seal and gasket.

[rodbolt17]

especially seals that will require power head removal to access.

kinda like reinstalling a clutch in an inboard without replacing the input and output seals.