2000 Yamaha 9.9 OIL LEAK FROM LOWER DRIVE UNIT

tinkering

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Yamaha 2000 T9.9ELRY 4 Stroke. Why is gear oil leaking from 2 of the 4 wee holes at the top front of the lower drive unit. I haven't noticed so far any oil throwing from the prop seal; haven't noticed any signs oil coming out of the water pump pee hole. The drive unit did have milky custard water oil. Which seal/s is/are the likely culprit/s? Could the shift rod boot be the problem; is it a combination boot and seal? If the pinion shaft seal is leaking wouldn't there be oil coming out with the water at the pee hole?
 

99yam40

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Re: 2000 Yamaha 9.9 OIL LEAK FROM LOWER DRIVE UNIT

pressure test lower unit to see what is leaking
 

tinkering

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Re: 2000 Yamaha 9.9 OIL LEAK FROM LOWER DRIVE UNIT

pressure test lower unit to see what is leaking

What is the easiest way to do that? Does this sound right?:Take the LDU off, use compressor with rubber nozzle tip at 5 to 10 lbs (pressure it with what kind of fitting/ what hole?); turn LDU up side down etc. and wait to see and hear the oil and air seepage? I imagine the LDU will have to come off for that?
 

tinkering

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Re: 2000 Yamaha 9.9 OIL LEAK FROM LOWER DRIVE UNIT

What is the easiest way to do that? Does this sound right?:Take the LDU off, use compressor with rubber nozzle tip at 5 to 10 lbs (pressure it with what kind of fitting/ what hole?); turn LDU up side down etc. and wait to see and hear the oil and air seepage? I imagine the LDU will have to come off for that?

A one way valve would be handy.
 
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