175 BlackMax Lower Unit Removal Help!

[MarshMan73]

I've got the manual. I've got the tools. I got all the bolts loose and the anode removed and hidden bolt removed, but I still can't get the lower unit to seperate from the tailshaft by more than 1/8". It seems to be binding on the front center stud. The nut came off easy enough and the washer was rusted out underneath it. I have tried soaking it down with WD40, and heating it up with a propane torch to no avail. I have even tried using the force of the side nuts to push down on the lower unit. I've tapped on the stud with a block of wood and hammer. Not budging. Any tricks to getting this front stud to break free? I assume that it's not being caused by the driveshaft or the shift linkage? Help?
Just to double check myself. I have have removed the anode and the bolt underneath, the two nuts on the underside of the cavitation plate, the two nuts on the side of the lower unit, and the center bolt at the front.

 

[cannonford57]

Re: 175 BlackMax Lower Unit Removal Help!

not knowing if it is or not a saltwater motor i have seen the driveshaft splines "grow" to the crankshaft on both if it was used in very brackish water

 

[MarshMan73]

Re: 175 BlackMax Lower Unit Removal Help!

Yes it's used primarily in salt water, how will I get such a thing apart if this is what has happened? Looks like it's mini-maul on the front stud time or no new water pump.

 

[MarshMan73]

Re: 175 BlackMax Lower Unit Removal Help!

Beat the snot out of the stud at the front of the lower unit to get the lower unit to come down, but it won't budge. Beat the stud so bad, I'm going to have to cut off the top 1/4 of the stud to get a nut back on. What else can I do? I'm running out of ideas except to put it back together and just leave well enough alone until the pump goes out and then I will shut it down and bring it to the boat shop and let them deal with it.

 

[MarshMan73]

Re: 175 BlackMax Lower Unit Removal Help!

I put it back in the water today and noticed that with a 4 people onboard and a cooler full of ice and drinks and a full tank of gas that the temp gauge was reading 1/2 gauge while on plane. It used to be 1/4 gauge. Will go to 3/4 gauge if you troll at 2000 RPM or so. Brought it back in and the tell tale is definetley gettig weaker. I knew it was time for a pump.
Ok now that I got her back home, does anyone have any suggestions on what to do next? Should I break out some prybars and give it a shot, tie the lower unit onto say a post and put some pressure on it by pulling the boat some or just throw in the towel and take it to the boat shop?
Will a boat shop even touch an old 1986 motor like this?

 

[Chris1956]

Re: 175 BlackMax Lower Unit Removal Help!

A 1986 motor should have a stainless steel driveshaft, however, I think they can still stick into the crankshaft.

The LU is a pretty precise fit. You are not cocking it such that it jams are you? I would also think if the front stud was loose, the LU would move a bit as the driveshaft bent a bit. That movement will tell you the crank to driveshaft connection is the problem. Is the shift shaft coupler loose?

One radical idea is to hang the motor upside down, from a tree or something, and inch off the ground, and spray PB Blaster into the 1/8" crack, hoping to get some to run down the driveshaft into the cupling. You would spray it ofter and let it's weight provide the motivation to seperate

 

[MarshMan73]

Re: 175 BlackMax Lower Unit Removal Help!

Got that sucker to move! Took a little convincing with a pickle fork and it was ugly what I had to do to it, but it's out. The front stud was frozen in the tailshaft because somebody put a zinc washer under the nut on the front stud. All the corrosion went all the way down to the lower unit. I seperated it 1 inch and then couldn't get any more leverage. I took out the sawzall and cut off the stud so I have 1 inch of usable stud coming out of the lower unit. If I have to have the front stud I will weld on some threaded rod and enlarge the hole in the tailshaft slighlty to accomodate the weld.
What you think? Does it need the front stud or can it live without it?

 

[MarshMan73]

Re: 175 BlackMax Lower Unit Removal Help!

Everything is cleaned up and back together and after letting the silicone dry gave it a test fire. Everything is much better except the missing front stud and rear bolt. Also looks like an alligator gnawed on the side of the lower unit I was using the pickle fork on. Guess I'm going to the Merc dealer and see if I can get a new front stud and rear bolt. Got much colder temp on the hose than before. Thermostats still open and close real strange on the hose. Sometimes there's a pause between the blasts of water coming out the telltale. Heads feel warm, but not hot, both are equal. No water coming out anywhere else it shouldn't. A quick rev up to 3000 gets a little water out the exhaust, but not much. After shutdown and 1 minute wait, the telltale comes back almost right away. Before there was a long wait for water.
Does this sound like cooling system operation? Seems to even run a little smoother now. I even hooked the idle stabalizer back up for fun and even seems a little smoother when it gets real slow almost ready to die after starting it. Maybe this will stop me having to rev it up first to warm it up before it will idle.
Thanks to everyone who helped out with advice to keep me going. Saved me big$$$$$ I'm sure from the boat shop.

 

[Chris1956]

Re: 175 BlackMax Lower Unit Removal Help!

Front stud is easily replaceable. Turn the old out with a pipe wrench. Install new one with some epoxy. Stud should have SAE threads on one wnd and USS threads on other end.

Glad you got it out. Bondo covers lots of sins...