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Evinrude sportsman 4425 gearcase leaking oil

1

15evie

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I have 1950 Evi 4425 1.5hp that is leaking gearcase oil! Strikes me odd that upper plug has gasket and lower(drain) does not(or does it)!So I look at prop shaft seal SKF-4770(will that work?)! Is that old grease that need to be removed and replaced(pic 1)? I also found a little washer(red arrow) that was up against seal(pic 2 blue arrow)!Anything need replacing here? 003.jpg002.jpg
 
Isn't the drain plug a tapered pipe thread?

As I seem to recall the original seals were somewhat special. Probably needs or has gotten some modification.
 

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Look again. That is a 1/8" NPT (National Pipe thread) (tapered). In case you don't know, pipe thread sizes are a relic of the days when iron pipe was measured by the inside diameter with allowance for corrosion build-up.
 
Thank You, I solved the leak problem with some JB WELD on the threads and around hole(drain plug)! Drain hole was POORLY designed!
 
Really nothing wrong with the design, but some owners were careless when handling the plug. I have used a little liquid Teflon when the threads get a bit messed up, sometimes from hitting a rock just right. The beauty of pipe threads is a natural tapered seal that the mechanic can run in a tap a bit deeper, then just seal the plug with Teflon tape. Still have several of these motors around. The skeg and gearcase design is brilliant for running in poor conditions.
Another noteworthy goal was to angle the propeller downward to provide lift to the Stern and when running in shallows with the motor trimmed up, the thrust direction will not push "stern down". As I age and understand engineering of the past, I appreciate it more and more. 3.5 million trucks have just been recalled for brake problems. WTF?
 
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