punctured gear case?

Hi.... Today I snagged a decoy line on with my 18hp tohatsu 2 stroke and I think the steel weight punctured the gear case on the opposite side to the drain plug. By saying 'I think' I punctured it I mean the hole is a very uniform approx. 5mm hold with a slight indent. But the indent and hole looks too unifrom to be a puncture. However, engine lost power and conked out but would start although I didn't want to force it so turned it off again. I stripped housing but don't see any sign of other damage. Can I weld/seal, re-build and continue use or could I have caused other damage?

Picture of the damage ???------------------------Have you looked at another lower unit ???------------Have you pressure tested the unit ??--------Was it leaking oil ??

I will post a picture as soon as I can! Didn't pressure test as oil obviously leaked out through hole! Mechanic reckons all gearing etc is sound and that I would be mad paying top dollar for dealership repair and that he would get prof. welder to repair and all will be fine. I am in two minds though, but I would say all looks good with no debris in remaining gearbox oil etc...Only happened today but have tried to view another unit but I can't find one on net or local. The hole is adjacent/within what looks like factory indent but this indent (or bolt hole minus bolt lost from impact??). Don't want to get it welded up if it should be plugges with bolt that holds shaft housing. Sorry for vagueness!

It would not be cost effective to buy a new gearcase to repair a small hole. Assuming you have an M18E2, the factory part would be 3V9S600000 GEAR CASE ASS'Y $270.98, which is probably the value of the motor +/-. If the hole is merely a leak, and not structural, it could be repaired by either welding, or filling it with a good epoxy putty, or drilling and tapping it to accept a spare drain plug and gasket, which could even be just any short bolt. OTOH, if there is a crack in the housing, that may or may not lend itself to a repair. In that case, you might be looking for a donor motor that has a blown powerhead, etc., or getting the new gearcase.

Try JB Weld.Have used it to repair cracked engine blocks with great results.It can be drilled and tapped if needed.

Thanks for the reply guys. I eventually got a look at a similar motor and it turns out that the damage to the housing is only minor and occurred around a factory inlet/outlet (that I don't know the purpose of and which wasn't shown in any manual or parts list??) that already existed. Therefore luckily what I am looking at is not a puncture but a large paint chip as a result of the impact. I think I might just re-build, top up with oil, and see what happens. However, I don't understand why the motor conked out a couple of times after the incident as this is the symptoms that led to my initial concern. Is there any reason why the motor would have stopped and is there anything else I should check before starting my motor? Also, any recommendations on gear oil type? Any advice is much appreciated..

As I suspected in post #2 ----not a puncture !!--------------It is possible that a flywheel key sheared from a sudden stop of the motor and it is worth checking that.

Obviously I should check the flywheel before I try to start the engine again or would you notice by pulling the starter cord?

Your paint chip is likely near a drain hole -- it's there to allow water out so it can't freeze. Any decent SAE 90 hypoid oil is fine. Just don't use the Type C oil that was used for electric shift OMC LU's. In order to check the mag key, you would pull the flywheel.

Got all checked re-built and everything is running real sweet. Would like to thank you guys for all your help and advice after my first post on such a forum.... really appreciated! Will continue to read posts etc but hope I don't need any such advice for a while. If I do however I know where to go.