Drive oil Leak and Preasure Testing

Hey guys, got an issue with my 94 mercruiser Alpha 1 Gen 2. 350 SBC. The gear oil resevoir was slightly low last weekend. 1 inch below top line. I topped it off, and ran all weekend, and it hadn't moved. Then took it out yesterday, and ran for 1 hour. Got back to ramp, and barely any drive oil in the resevoir on the engine. Looks like it is going into the bilge area, but not sure. There is surely some oil there, but not a lot. Anyway, I have read here to plug the oil line going to the resevoir and preasurize the foot. Where do I put the air. (drain hole on the lower unit?)

If I had a full resevoir, and then lost all of it after running for an hour, I should be able to find it pretty quick I would think!

Thanks

Michael

Re: Drive oil Leak and Preasure Testing

If your leaking oil and it's comming back into the boat and you can't see it it's probably leaking around the front u-joint yoke.
Drain the unit and pressure test from the top screw hole.At the yoke you won't be able to see it leak unless the drive is off.
It only needs 11# of pressure to test,be carefull as you can do damage to the other seals.Jerry

Re: Drive oil Leak and Preasure Testing

Thanks! What tool is being used to preasure test this? I haven't seen any oil on or around the foot. It is only inside around the engine. I will see what I can come up with!!

Re: Drive oil Leak and Preasure Testing

I have a mercruiser 140/MR stern drive unit. I have recently noticed oil in the bilge area - below the motor. Trim pump is full, no change on dip stick of motor. Did change oil in foot, but did not get much. Pumped in 32 oz. and never came out vent hole.

Took it out yesterday and after 4 hours of running, had a little oil again in the bilges, mixed with a little water.

I've only owned the boat for a month (bought at an estate sale), but this thing might have been sitting for years in a garage as it "looks" that way.

I will try the pressure test as indicated in the service manual, but just wanted to see if there was a resoultion to this post?