leaking gear lube

2023 250 Pro XS 4 Stroke
Serial # 3B382810

Picked up my new boat on 5/2/2023. Did the first 2 hours of break-in. No sign of gear lube leaking.

After first fishing trip noticed gear lube leaking (2.6 hours on motor)

Took boat into dealer and the lower unit was drained, pressure tested, and yellow gaskets around drain and fill holes were replaced. No leak detected when pressure tested.

Fished a full day on May 21 no leak observed.

Fished a half day on May 25 no leak detected.

Walked behind boat today and noticed gear lube leak again.(Motor has 7.0 hours)

Will get it into my dealer ASAP.

Any thoughts as to what could be the issue!

Thank you!

Where do you see it leaking? If it's running down the skeg,it could be coming from the prop shaft seal or the fill bolt gaskets.

It is running down the skeg. Thank you!

More than a fair chance you have a leaking seal behind prop. Check for line behind the prop. Should do a pressure leak-down test. Good luck with finding and repairing the problem!

Thank you!

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Originally Posted by kbm

Thank you!

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Come back and tell us what problem/fix was! Help folks learn!

Will do! Getting in to the dealer on Monday morning.

UPDATE: Merc Technician pressure tested the lower unit and no leak was indicated. Drained the gear lube and detected water in it. So the plan is to order a complete seal kit for the gear case and replace all seals. Should be back on the water next week!:smile:

Hard to believe the pressure test didn't show anything. I bet it would have if given a few hours but maybe not necessary IDK!

Quote:

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Originally Posted by kbm

UPDATE: Merc Technician pressure tested the lower unit and no leak was indicated. Drained the gear lube and detected water in it. So the plan is to order a complete seal kit for the gear case and replace all seals. Should be back on the water next week!:smile:

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If those items were performed in the order listed, THAT would be why the leak wasn't detected.

ALL lube must be drained, water pump must be removed, test performed at multiple pressures while rotating ALL shafts and checking for leaks with soapy water (kiddie bubble mix works AWESOME).

If no leak is found- it's almost always the drain or vent screw seal(s).

After what Don said........I would be looking closely at those areas where gaskets seat on the drain and fill points. A burr or slight void would make gasket seating difficult.

Quote:

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Originally Posted by EuropeanAM

If those items were performed in the order listed, THAT would be why the leak wasn't detected.

ALL lube must be drained, water pump must be removed, test performed at multiple pressures while rotating ALL shafts and checking for leaks with soapy water (kiddie bubble mix works AWESOME).

If no leak is found- it's almost always the drain or vent screw seal(s).

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Thank you!

Quote:

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Originally Posted by 5keepers2

After what Don said........I would be looking closely at those areas where gaskets seat on the drain and fill points. A burr or slight void would make gasket seating difficult.

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Thank you!

Quote:

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Originally Posted by 5keepers2

After what Don said........I would be looking closely at those areas where gaskets seat on the drain and fill points. A burr or slight void would make gasket seating difficult.

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I think Don meant to read his post carefully. He described how to properly check for a lower unit leak, that required no fluid and the water pump removed, and then after it was pressurized you rotated the input and the prop shafts (shafts could have run out or have worn areas at the seal interface) to check for leaks. I think he said if you do all that in the correct order and find no leakage, then it often turned out to be the fill or drain gaskets / screws / interface. However, if you did not use the procedure he mentioned to check for leaks, I think all bets are off on the fill and drain plugs, if I understood his post correctly.

Quote:

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Originally Posted by Pulsare2020

I think Don meant to read his post carefully. He described how to properly check for a lower unit leak, that required no fluid and the water pump removed, and then after it was pressurized you rotated the input and the prop shafts (shafts could have run out or have worn areas at the seal interface) to check for leaks. I think he said if you do all that in the correct order and find no leakage, then it often turned out to be the fill or drain gaskets / screws / interface. However, if you did not use the procedure he mentioned to check for leaks, I think all bets are off on the fill and drain plugs, if I understood his post correctly.

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Yes indeed. I understood. I will check with the tech that is working on the problem to see if the proper procedure was followed. Thank you!