gearcase drain plug leak

[TownsendsFJR1300]

Spec's are to hold 10 PSI for 10 seconds with no leak-down/ leakage.

At least for my F150:




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[zenoahphobic]

I would have though a couple of PSI would be adequate to simulate actual pressures encountered in operation.

10 PSI, although clearly specified in the drawing, might be a tad too high in that it might actually make the seals seal better by pushing them harder against the shafts, thereby masking the possibility that they maybe actually not be quite tight enough fitting (worn out or hard), allowing some water to pass through under normal operating pressures.

[TownsendsFJR1300]

I would have though a couple of PSI would be adequate to simulate actual pressures encountered in operation.

10 PSI, although clearly specified in the drawing, might be a tad too high in that it might actually make the seals seal better by pushing them harder against the shafts, thereby masking the possibility that they maybe actually not be quite tight enough fitting (worn out or hard), allowing some water to pass through under normal operating pressures.

There's really nothing moving inside to make pressure (like a piston going up and down).

The PSI is just to make sure the unit is sealed tight and water will NOT intrude (or oil leak out). 10 PSI for such a short period is plenty to make sure the LU is water tight (which is the bottom line).

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[pstephens46]

Such an easy, quick test as shown by Scott's post. Amazing the pages of posts over at THT on leaking lowers. Just a simple test, that's all.

[99yam40]

I believe Yamahas have the seal lips toward the outside so the inside pressure would not help to push then against the shaft

[TownsendsFJR1300]

Such an easy, quick test as shown by Scott's post. Amazing the pages of posts over at THT on leaking lowers. Just a simple test, that's all.

The LU oil DOES have to be removed for testing purposes...

[pstephens46]

The LU oil DOES have to be removed for testing purposes...

Absolutely. Oil is about $10. No one has a right to complain either. "Oh I just had it changed at the dealer. I can't believe there is an issue"

I am not ragging on the OP. Just amazing that some on other sites make things so hard. Such as advice like this. "To find a leak, wait until nighttime. Get a flashlight with a purple lens. Lay down on back under lower unit with light and wait for a dribble. Could take awhile"

Or my favorite. "Go out and sniff your lower unit. Lower unit oil is stinky"