1972 johnson 20hp, lower unit/impellor

[jwilkey84]

I just got a 72 20hp johnson and it runs, but not well, so I started taking things apart. I started with taking off the lower unit, to find that the impellor is missing 4 of the 6 wings. Then I removed the metal plate that the impellor sits on to do some futher cleaning and stuff. My question is, between that metal plate and the lower unit housing below that it sits on, is there supposed to be a gasket? I was thinking on the last one I did, there was a gasket. This new one, was stuck on like it was sealed, but there was no gasket. there was a little residue, like maybe somebody used some rtv silicone or something. BTW is it OK to do the same when I put it back together? I think the waterpump kit includes a new gasket, but I would rather just buy the impellor and use some RTV silicone if that is permitted.

 

[F_R]

Re: 1972 johnson 20hp, lower unit/impellor

There is not supposed to be a gasket in there. However, you are supposed to clean it up and use some kind of a sealant. Sounds like the last guy did good.

 

[jwilkey84]

Re: 1972 johnson 20hp, lower unit/impellor

cool. what kind of sealer should I use? Is there a special kind?

 

[HighTrim]

Re: 1972 johnson 20hp, lower unit/impellor

Gasket sealing compound. Use it on the screws for the impeller housing as well. Grease the splines on the drive shaft. Oil the impeller blades. Make sure you line up that water line with the grommet on top of the impeller housing when lining her back up, they get knocked askew easily, restricting water flow and causing overheating.