Is this a crack in the lower unit??? (Photos)

I have an more extensive post on the two oil issues I have with my 2000 50hp 2stroke here:http://forums.iboats.com/showthread.php?p=2797670#post2797670

but I wanted to have everyone give this seam/crack on the lower unit a quick look to see if this is suppose to be there or not. I just got back from a 1000 mile round trip and it was the first time I used a transom saver but now I have this spot where some oil has appeared and I do not recall this seam or line previously and from the looks of the blown up image from evinrude.com there should not be a seam there.

What is everyone's opinion on this? If it is a crack is this an easy weld fix?

MiNoobie said:

The more I look at the point where the oil appeared today just above the lower unit, the more questions I have. In these images, is there suppose to be something (rubber plug?) in that square hole. Also, is that line (light gray from where paint has flaked away in top image) on the lower unit suppose to be there that travels down or is that a crack or split in the weld? I do not see any other split like that in the lower unit housing.

Here is the parts manual photo and there is not visible seam on that part of lower unit (gearcase).

Click to expand...

Any input on the original thread is also greatly appreciated!!! Thanks in advance.

Re: Is this a crack in the lower unit??? (Photos)

I just went outside to double-check, and it looks like there is in fact a seam there (at least on a much older 3-cylinder, there is, and these things are pretty consistent). Manual calls for a sealant there, OMC Adhesive M, which was superceded by 3m #847, although permatex #2 works just fine, and some people don't use anything at all. That area does not have to be water-tight. In fact, water comes out that hole when the muffs are on. Gear oil couldn't leak there because of gravity. Just looks a little greasy.

The flaky paint looks a little...flaky, but otherwise it looks to be in normal operating condition.

Re: Is this a crack in the lower unit??? (Photos)

Check the gear oil and see if water has gotten into it. If not, then you have no worries. Most likely what you are seeing, is unburnt crankcase oil. Very common with 2 stroke outboards.

Re: Is this a crack in the lower unit??? (Photos)

I was thinking the same thing as 1946Zephyr.
Good Luck

Re: Is this a crack in the lower unit??? (Photos)

no crack there.unburnt oil also ,not a big deal atall.

Re: Is this a crack in the lower unit??? (Photos)

Since this appeared after I just trailered it 500 miles and it has not been in the water since it was spotted, should I wait to check/change the gearcase oil until after I have had it submerged again? My thinking is that if that "leak" happened when it was on the trailer then no water would have entered the oil on the lower unit yet and I should give it ample opportunity to test it.

If I do that, I will go to one of the smaller local lakes and just run the motor for a few minutes to the fishing spot, let it sit in the water for a few hours while I fish with the trolling motor and then run it again back to the launch. Probably only a 2 minute run each way on the motor.

Good idea?

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Again, thanks for the feedback and for checking on your own motors! Greatly appreciated.

Re: Is this a crack in the lower unit??? (Photos)

If you have water in the lower unit it will still be there. When was the last time you check it or had it checked?

If you want to check it just pull the bottom plug and let a little bit of oil run out just a tsp. will do if you get water first then it's time to change the oil. If you find that you have a lot of water then you may have more trouble than you think.

If you do in fact fine a lot of water you can try changing the oil and install new seals on the screws run it in the water for an hour or so and check the oil again if you find water again then you will need to have the seals replaced and be sure the unit in pressured tested by who every does the work before it goes back in the water or play it safe and check the oil again after running for an hour or so.

Take Care

Re: Is this a crack in the lower unit??? (Photos)

the top of the gearcase is below that spot, so gear oil would have to defeat gravity and travel uphill to get there. And then you would see a line of it running down and dripping off the antiventilation plate there in front.

Unless you were in an accident, or dropped a trailer wheel off a culvert, or locked up a hub at 70 mph or experienced some other kind of trauma, you didn't damage the lower unit by trailering it. There's just been too many millions of trailer miles put on boat motors over the last 50-odd years, for yours to be the first.

[p.s. I know tphoyt is not the only boater who will accept a little bit of water in the gearcase, but for the record, there's another school of thought that says any water at all is too much. But in any case if you do find water, tphoyt's advice to replace the o-rings and try again is for sure the next step.]