'70 25 hp evinrude - weird lower unit leak

So, I was going over my new-to-me 25 hp after running it for the first time last weekend. There was a small amount (maybe a tablespoon) of water in the LU, and I noticed a small amount of LU gear oil leaking from the water intake port on the left side, and sitting on the cav plate.<br /><br />So, I pulled the LU, removed the water pump and would've bet $$ that the driveshaft seal was leaky... the seal looked ok, and I did presure test and found it did run down slowly... put LU in water, and found a slow leak from the front screw holding the water intake plate onto the lower unit. If you remove the screw, the hole goes straight through into the lower unit cavity. There's no seal or anything on the screw, or behind the plate.<br /><br />I cleaned it up and put some "make a gasket" on the threads and re-installed. I figure it should be OK now. But, is this a case of a machining mistake or something? Seems like it should probably be a blind hole, not all the way through. Or is there a gasket or something that mine was missing? I do have the service manual.. doesn't show any gasket or anything.<br /><br />thanks... <br /><br />Brent

Re: '70 25 hp evinrude - weird lower unit leak

Brent, your right. This screw SHOULD NOT go all the way into the oil cavity. Could be the previous owner may have tried a longer screw that punched into the cavity?....dunno. Keep an eye on the gear lube though. If it don't leak under pressure test, should be good to go. <br /><br />Keep us posted....thanks.

Re: '70 25 hp evinrude - weird lower unit leak

the screws definately look original... they have the original blue paint on the tops, and have the right shape to mate into the intake plate... threads in the holes look good all the way in, not monkeyed with. <br /><br />My guess is this small leak could have been this way for a looong time. Goes to show how a pressure test helps! I'm glad I didn't start breakin' the seals apart, even when I was "sure" it was a leak at the base of the water pump. <br /><br />Brent

Re: '70 25 hp evinrude - weird lower unit leak

Yeah....know what ya' mean....been that route. Always good to check the "obvious, easy stuff" first....then go for the "other".<br /><br />Good goin Brent!