OK, I just took my boat to be winterized but was told by the mechanic the block has an external crack - maybe one on each side, I was so depressed i forgot, I'm going to see it today. Anyways, I am now trying to figure out what caused this. He assumed it was from improper winterizing last season. however, to make a long story short, I purchased this engine used last year so it was installed this past Spring. The relatively inexperienced guy i had install it says it was not cracked at the time (he didn't sell it to me and is a friend so he wasn't screwing me).
Mercruiser 350 Mag engine. Fresh water only. The engine was performing fine all season. I did watch it run early in the season and the water pump was leaking a bit - replaced by the mechanic then no leaks that I or he ever saw. I am fairly sure no water in oil, but I'll find out more on this today. I don't recall watching it run uncovered after the following problem happened. I do not think my temp gauge works properly.
I'm wondering if it cracked this boating season when my outdrive oil leaked out causing my upper gears to fry. I was out on the lake when this happened, but I didn't know what the issue was, only that the prop wouldn't turn. So I tried a few times to get it going, meaning I ran the engine for a while (no idea how long - maybe too long). I assume this condition causes the impeller to not function so I was likely running without cooling water. Could this cause a cracked block???
Aside from improper winterizing, what else can cause the block to crack?