Re: 1957 Evinrude Fleetwin 7.5 Water Discharge is HOT

[Don]

Well, I doubt the impeller plate is at fault, but surely worth checking while you have it apart. It is very important that the SS plate be well sealed to the gearcase housing, or the engine will pull exhaust through that joint instead of water at higher speeds. Sometimes the thin aluminum under the plate gets corroded/eroded away causing a leak as well. This area is best sealed using the OMC "type M" sealer which squeezes from a tube. The stuff is a little messy but dries quick and hard. I think it also goes by "847" if bought from Loctite. I would not use any sealer in between the aluminum impeller housing and the SS impeller plate, just clean the mating surface of the aluminum impeller housing and install it "dry" against the SS impeller plate. Using sealer in this area could weep into the area the impeller spins in and hamper its performance.
Like I say, we have heard this type of complaint before on the 10hp models. We found that there is a little bleed hole in the powerhead to spray a bit of cooling water directly in the top of the exhaust housing to keep it cool…Perhaps the fleetwin models have a similar bleed hole. I will have to look at a powerhead when I get home…