Question about reinstalling lower unit

[thormx11]

I have the lower unit off of my 1987 Mercury 80hp outboard to put some new gasket in. When I removed the lower unit, it had a silicone seal inbetween the lower unit and upper unit. Is this seal really needed? I have about a 1980 Mercruiser 898 inboard and when I worked on the lower unit of this engine, there was no type of seal between the upper and lower unit.

Not sure If the seal was just something somebody added, or if it is really needed.

 

[James R]

Re: Question about reinstalling lower unit

Not necessary. Silicon is never used to seal a lower to the housing except by someone that does not know.

 

[aussieflash]

Re: Question about reinstalling lower unit

Do you mean the seal on small divider plate behind water pump,which is normal to keep out exhaust.Don't think its needed on all mating surface.Cant see it causing a problem either way.

 

[thormx11]

Re: Question about reinstalling lower unit

I'm talking about on the top sides of the lower unit, not the water pump, where it joins with the upper unit

 

[Chris1956]

Re: Question about reinstalling lower unit

yes, a seal of anykind on that surface is unnecessary.

Aussie, We never seal the divider on an inline motor. I never sealed on on my V6 either...it had a rubber seal on the exhaust tube.

 

[aussieflash]

Re: Question about reinstalling lower unit

yes, a seal of anykind on that surface is unnecessary.

Aussie, We never seal the divider on an inline motor. I never sealed on on my V6 either...it had a rubber seal on the exhaust tube.

Thanks Chris,I meant the small divider block which does call for silicone when installed.