Yikes!!! Water in lower unit....pressure test passed..what now?

[Imtrying]

Took my 70hp Johnson out the other day to do some testing of the tach, and the tack failed, but motor ran fine...35 mph. Ordered a new tach, waiting to get it so I can install it. Another problem occured...decided to drain lower unit that I rebuilt...MILKY WATER!! Ran the motor about 15 miles total with new oil in lower unit. I did a pressure test with a hand tire pump. Filled a plastic tub over the first joint of the lower unit. Had a good seal on the pump cuz it didn't "bubble" at the connections. (drained oil, put screw in lower hole, attached hose to upper screw hole) It didn't bubble up any where else either!?! All new seals installed. Drive shaft, and prop shaft looked good too, no wear on either shaft. No metal on the lower magnet screw. Where could the water be coming from? I got this motor for nothin, and all the rebuilt parts too! It's a great running motor, but the water in the lower unit really puzzle's me. HELP!!! TIA Dan

 

[clanton]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

The pressure test only verifies that the oil will not leak out. The vacuum test will verify that seal that keeps water out is good..

 

[alcan]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

Hi Imtrying<br />Start with the most simple thing. Did you install new oil plug gaskets. Those little buggers often leak when used again. You need to perform two leak tests. Most guy's figure that a presure test alone is good enough. This is not allways the case. Do a vacuume test as well. It is quite common for a L/U to pass one test and fail the other.

 

[JB]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

Did you put new gaskets under the drain and vent screws? That is where water often intrudes.<br /><br />Good luck.

 

[Imtrying]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

Did not put new oil plug gaskets on the screws, but did wrap some teflon tape around screws. The gaskets were kinda hard...will replace them first....How does one preform a vaccum test, other than taking it to a marina? Dan...

 

[R.Johnson]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

Keep in mind that a vacuam , or pressure test is a static test. If the prop, or drive shaft seal surface has a deep groove, or worn surface, it can pass this test. When running with a worn bearing, or bushing, you can have a leak, even though it will pass the above test's. A seal is just that, " A Seal" it will offer no support to a worn shaft.

 

[DJ]

Re: Yikes!!! Water in lower unit....pressure test passed..what now?

Teflon tape around the drain/vent screws is not satisfactory.<br /><br />Replace the gaskets. Get some spares too.