Re: Another impeller question
I use Permatex #3 Aviation-Type non-hardening gasket dressing between the pump plate & gearcase, and also between the pump plate and water pump housing. If you assemble with 'dry' surfaces it's likely not to pump. Have never had any pumping problems using Permatex.
If you use an RTV-type of sealer, apply a very thin coating to the surfaces. You don't want to lay it on thick, because the excess will squeeze out then harden and the hard chunks will break off & go places you may not like them to go!
Automotive-type Red, Blue, or Black RTV is suitable for this application but don't use the Ultra-Copper as you don't want any copper-bearing ingredients against aluminum.
HTH..........ed