Loosing lower unit oil

[zzz]

I have a strange problem with my 1999 200 (3.1) Yamaha lower unit. The oil is disappearing. It is not leaking out on the ground and there is no water getting in. I have changed all seals, o-rings, prop shaft and prop shaft housing needle bearing. I am loosing approximatley 8-10 oz. in 20 hrs. of running.

 

[rodbolt]

Re: Loosing lower unit oil

double check the drive shaft seals, make sure the slinger between the impeller wear plate at the drive shaft bearing housing is in place.
the water pump can actually suck oil past those seals.

 

[zzz]

Re: Loosing lower unit oil

Thanks a million for the info you are the first to tell me if I am not leaking oil on the ground or getting water in the oil then I must not be checking it right. I checked the parts list and the only part between the water pump plate and the bearing housing is the oil seal cover. Is this the part you are referring to? Again I want to Thank You for your help!!!!

 

[rodbolt]

Re: Loosing lower unit oil

thats why I say double check it.
yes its that cover, even with the cover there if the seal leaks it can allow oil to be sucked up the water pump.
next time the water pump s apart check it and take a thin blunt object and gently move the seal away from the shaft. if its milky its been leaking.

 

[hunter1997]

Re: Loosing lower unit oil

ZZZ
I have the exact motor only 1998 with the exact issue. Did you try to replace this seal and did it solve your issue? I have owned my boat for five years with same issue

 

[JB]

Re: Loosing lower unit oil

If you loose it you will surely lose it.

Howdy, Hunter.

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