1964 Evinrude Fastwin Impeller / water leak question

[j5wentworth]

Greetings,

Looking for a little input here. I have a 1964 Fastwin, 18hp that I inherited. It was sitting for years and was a strong runner last I recalled. I replaced the impeller on it along with all lower unit seals, shift link o-ring and bushing, oil fill/check screw seals, etc. I noticed in the parts diagram that there is no gasket utilized with the impeller housing, which seems odd to me, since other HP fastwins do. Reason I am asking is because I am getting a small amount of water into my lower unit. I keep thinking my impeller area is to blame because of no gasket, but the diagram says otherwise. Is this right?

Only other thing I could think of is there is a small hole ( from the factory) in the side of the housing between the oil check and fill screws, that a very small amount of gear oil appears to be coming out of. Thoughts?

 

[boobie]

Have the lower unit pressure and vacuum checked and then you will know where the leak is.

 

[oldboat1]

Might not be gear oil leaking (smell it -- sulphur smell is gear oil). You can pressure and vacuum test yourself, if inclined. For pressure testing, need a hand or foot pump (bicycle pump) -- empty gearcase, immersed in water. Look for bubbles to identify leaks.

 

[j5wentworth]

No Title

Welp, I dropped the lower unit and pressure tested with a DIY setup using a bike pump and soapy water. All the seals were good but I could hear air seeping out somewhere. After about 30 mins of searching and head scratching, I found that the factory tapped hole in the housing was leaking and blowing bubbles. I don't understand what it's for because it's not threaded and it's a dead end hole (supposed to be I assume). Somehow it has a hole in it. Any insight as to what this hole is for and if I could just JB Weld it?

 

[F_R]

I really don't know why that hole is there, but my unproven suspicion is that it is for a locating pin to position it in a jig during machining. Whatever, it is not supposed to go through. Maybe somebody made a misguided attempt to open up what they thought was a drain hole. Plug it up.

As for the water pump, no gasket. Good practice does say use some sealer between the plate and gearcase to prevent the pump from sucking air. But that has absolutely nothing to do with water getting in the oil.

 

[oldboat1]

Just a thought -- maybe you are pressurizing water passages in the housing, and not the gearcase. I remove either the vent or fill screw, and use that -- needle adapter and a piece of gasket material. (Can be more sophisticated and buy a screw to drill, or repurpose the plastic fitting from an oil filler pump.)

 

[j5wentworth]

Just a thought -- maybe you are pressurizing water passages in the housing, and not the gearcase. I remove either the vent or fill screw, and use that -- needle adapter and a piece of gasket material. (Can be more sophisticated and buy a screw to drill, or repurpose the plastic fitting from an oil filler pump.)

I pressurized at both the vent AND fill screw holes (not at the same time of course). I used the threaded adapter for adding gear oil and connected that to a tire valve stem, which was connected to my bike pump. I know it was getting pressure in the gearcase because the driveshaft was wanting to shoot out. It makes sense that is where the leak was coming from because I saw a very very slow stream of oil leaking out of that hole and dripping down to the skeg and onto my garage floor.

 

[Chinewalker]

That's not the cavity drain hole - I'd do as FR says and fill it with JB Weld. Clean the be-jeepers out of it first, as any oil residue in the porous casting will make for difficult permanent sticking of the epoxy.

Not sure what Fastwins you're referring to, but I've never seen one with any gaskets above or below the water pump plate or housing.

 

[F_R]

Maybe the confusion comes from the newer motors (1982-ish) with similar gearcases, but with plastic water pumps? Yeah they got gaskets, but are different critters.

 

[F_R]

delete

 

[oldboat1]

Just for grins, could try pressurizing through that hole, leaving the drain or vent screw slightly loose (look for bubbles there). Don't overpressure when testing.

Seems like a pretty big hole on second look. Drain holes are pretty small. If you decide to fill it, might consider a short bolt along with some Marine Tex, after cleaning like Chinewalker suggests (some acetone or lacquer thinner).