I have a 2012 MB 45mag that has recently been upgraded to a 55mag. Last summer (prior to the 55mag mod) I had to replace the crankcase cover and gasket because the cover cracked and gasket broke. I replaced the cover with a new cover and ran it throughout this past season (upgraded to the 55mag right before last hunting season began). The gasket started to leak and I limped it through the season while it was leaking because it wasn't a terrible leak and I monitored the oil level regularly. I just got around to ordering my new gasket and bolt/stud kit this past week as season is quickly approaching. I pulled the motor apart last night and while I was cleaning everything up, there it was, ANOTHER FU**ING CRACK!! So, what gives? Why does this keep happening? I check torque on my bolts every so often and never get much out of them. I know you guys with build motors have better luck than this, so any input would be appreciated! I need to know what to do to get more than a season out of the case cover (you all know they aren't cheap)! Thanks in advance fellas!

Because briggs

I figured that would be one response! haha but what can I do to prolong the life!?

Out of balance internals, flywheels, props, outdrives, etc will find the weak links in that case/block. Some have better luck than others, but don't be fooled that anyone has an "absolute" solution for it.

One of the biggest problems I think and have seen many times. Is a inproper install of the exhaust system. Mounting brackets putting way to much force on the cover. I have seen the brackets flex when tighting them tight. Causing broken covers. when u install ur exhaust pay attention to the brackets. I also do a three step torquing of the cover bolts. Mark ur bolts when done than u can do a visual if they back off. I have seen factory exhaust with Same problems.

The Briggs bolts are cheap and they stretch and get loose. Did any of yours loosen up? Calen has the stronger bolts and engine covers.

I'm going to venture out and say rotating assembly is out of balance if this has happened a few times.

If gasket and stud kit comes today, that's our week end project on a 2013 MB7000. We are putting studs in block and not using bolts to attach cover. Mb says new kit doesn't come with the larger studs any more, just the two sleeves. Said a few guys were having trouble breaking them. This motor just turned over 100 hrs when gasket started leaking. I have put 64 hrs on my motor since installing block studs and the two larger MB studs, with out leaks, but when I installed the two larger studs I used a drill press to open up cover holes, to make sure they were drilled perfectly straight. IMO I think that's why the two studs were breaking that came with the old MB kit. May have been on a bind in cover, causing added side stress on the studs. I also enlarged the holes in the exhaust bracket that those studs went thru.

I just received the gasket, new bolt/stud kit from BPS (Micah), and I am waiting on my new cover to get here (should be Monday). If I remember right, the last time I did it, I used the old studs which was dumb on my part.

Are you guys saying I shouldn't have ordered the new bolt/stud kit from BPS? I want to make sure I do it right this time, but I am also on a budget... I did order a used case from a guy on eBay that came off of a motor that threw a rod. The case cover looked damn near brand new though.. I figured $90 vs. $400, I wouldn't be so upset next time it cracks...

Do you guys load everything up with red Loctite? Also, any liquid gasket around the gasket? I have heard yamabond or hondabond works well, but I'm not sure...

My case cover came yesterday and it looks pretty much new after I cleaned the old gasket residue off and cleaned out the cover with carb cleaner. I am going to start putting everything back together tonight, but am worried about the bolts instead of the studs... Will I be ok without the full stud kit? I still have the 2 longer studs like you have, but they came with regular nuts - should I get nylocs or double nut them? Also, I haven't opened my gasket up yet in fear of contamination, but does it not come with 2 new O-rings for the oil ports? Are we supposed to use the old O-rings?

Any opinions and tips for putting it back together are appreciated guys!!!

Where do I get them? Are they common size that I can get from a hardware store or do I need to order from somewhere?

I have no idea who could machine the cam and crank gear for me. I really don't have time to send the motor away to have it done.... I have about 3 weeks before we start goose hunting and I need to get out scouting before that.. My buddy's dad owns a nice machine shop, but I wouldn't have a clue what to tell him to do...

Still gonna leak.

Also sounds like he has bigger problems.

I already answered that question.

vibration

But that can't be it, cb. These briggs are awesome.

And you're wrong also, maxxis.

Lmao

CB you seen ones with case gasket eliminated leak?

Lots of em.

He's not just having a leak issue either, he's cracking the cases. Something is horribly out of balance.

The liquid sealer is ALOT better than the stock gasket, BUT eventually it will leak again. Typically I see the sealant as a Longer term fix. This guy needs to have his crank checked aswell as the flywheel.