Black Max 200-lower unit stuck on, need help please.

I need to replace the water pump and the LU is stuck. The back half will flex down a bit, but it appears that the front stud is stuck to the housing. The stud itself is rusty and the housing is pitted a bit around it. I just got the boat and know it's been AT LEAST 6 years since the LU was off, but don't know when. I put a piece of wood from the cone to the trailer and lowered the trim to put some pressure on it, backed the two front nuts against a piece of metal, heated the housing and stud back & forth (letting it cool in between), tightened and loosened all fasteners, penetrating oil, mallets, sweat, bruised knuckles.....All these have been done several times back & forth for hours hoping to get it to move, but nothing. So here I am, boat almost ready, right outside the window next to me. Are there any special tricks to try? I went easy on heating the housing, should I just go for it and not worry?-I think there's nothing sensitive near that front stud, but not sure and afraid to get crazy with the torch.

Off topic: did a carb/timing synch today and those motors that I thought ran well and needed nothing are AWESOME now. Bump the key and bask in the smokey crackle!

Re: Black Max 200-lower unit stuck on, need help please.

Up by that front stud is the seal for the shift shaft. If you're sure you have all 6 fastners (7 if you count the one holding the trim tab on) off then get some PB blaster and start soaking the studs with it. Keep soaking it and it will let loose. I've known it to take a couple of days but it beats the alternative of ruining the case.

It's not all that common but the drive shaft can become frozen to the crank. You need to pull the powerhead if that happens. Just thought I'd mention it but don't stress to much over it, it's really rare.

Re: Black Max 200-lower unit stuck on, need help please.

THANK YOU!
It's soaking in aerokroil right now. I gave up really trying after a few hours so for the rest of the evening I'll be going out there putting light heat and more oil on it. I'll hit it with some PB too, haven't figured out for sure which one's better yet. In the AM I'll give it another round of pulling & thumping and just keep on it 'till she gives up. I'm so close to a water test it's killing me, but this pump really has to be done for me to feel safe, even for a mild lake run.

Re: Black Max 200-lower unit stuck on, need help please.

Third day now of oiling, heating, prying, beating-front stud is still stuck to the upper and I'm pouring a cocktail before I loose my friggin' mind. This motor has a 5" extension housing (I think that's the right name) Will this come off with the lower, or is it attached to the upper somehow? I assume that front stud is threaded in the lower, slipped loosely through the extension to the nut above the upper?? Or is it threaded into the extension? I couldn't find anything on it in the merc manual.

I'm down to either trying to get a drill straight down the stud, or sawing through the front of the housing to cut the stud off. Drilling straight in the space given doesn't look easy. Is there anything in the extension housing foreword of that stud that I'll damage by sawing at the joint? Will the gap made by the saw have to be filled and sealed afterwords? Once I commit to destroying the stud my last attempt will be to twist it and see. I did already by double-nutting, but went a little easy on it to preserve it. I may weld on a nut and give it a good try.

Re: Black Max 200-lower unit stuck on, need help please.

I had a lower unit that was stuck on my 200 black max. I went nuts trying to get mine off. Turns out it was the drive shaft splines were stuck in the power head... just surface rust. I could not pull the power head either! I had to drive wedges in between the lower unit and the mid section. Take your time you don't want to breack anything! Ironically the reason I was taking it apart was to change the shaft length of the motor. If you have a spacer the studs are over 5" long. It is possible they are stuck in the spacer. I would unbolt the studs from the mid section and pull the spacer and the lower off together. Then work on getting the studs out on the bench. Careful application of heat to the studs on the bench might help loosen them up. lather them up with antisieze and grease the driveshaft splines when you put it back together.