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Please help! Infamous stuck sterndrive

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greichert1

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I recently bought a 72 kona with bad alpha one upper drive(stripped gears). When i prchased the boat, the stern drive was in-place but the drive yoke was detached and sitting in the boat... I had a local boat mechanic install a good used upper on my lower thinking that this would be a quick fix. I also replaced the water pump, gimbal bearing and all bellows while i had everything apart I have tried and tried to get the repaired drive back on the boat but have been defeated again and again. The alignment tool goes in smooth as butter and spline marks are even all around. (and yes the shift linkage is aligned) But the drive just wont go all the way on. PLEASE HELP before i just set it on fire. Thanks
 
greichert1 said:
I recently bought a 72 kona with bad alpha one upper drive(stripped gears). When i prchased the boat, the stern drive was in-place but the drive yoke was detached and sitting in the boat... I had a local boat mechanic install a good used upper on my lower thinking that this would be a quick fix. I also replaced the water pump, gimbal bearing and all bellows while i had everything apart I have tried and tried to get the repaired drive back on the boat but have been defeated again and again. The alignment tool goes in smooth as butter and spline marks are even all around. (and yes the shift linkage is aligned) But the drive just wont go all the way on. PLEASE HELP before i just set it on fire. Thanks
Click to expand...

How much further does it need to go? Sometimes the "O" rings on the input shaft, if new, make it a tad difficult to ram home the first time in. May take a little nudge / force to get them in. Be sure the "O" rings are lubed up so they slide into the bearing a little easier.

May be way off base here and thinking out loud here, and I don't recall seeing it, but does the gimbal bearing have camphered edge on one side to assist getting the "O" rings to slide in easier? If there is a campher and it's is on only one edge, and that edge is inboard and not outboard, then the bearing may be in backwards. Just a thought.

Stupid question, but are the splines and input shafts the same on the old and new input shafts?

Possibly the splines are not lining up with the coupling? Put drive unit in gear (forward or reverse) and turn the gears in the drive unit by turning the prop shaft by hand (set the prop on the shaft to faciltate this). That would align the splines, if that's what's keeping her from going on. Have had to do that before on my drive units.
 
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Thanks for the quick reply, I appreciate any advice. The Drive only needs to go on another inch or two. It stops just shy of being able to thread a nut on the housing studs. I also assumed the O-rings could be the culprit but ive tried installing the drive with all the O-rings removed and still nothing. Im not 100% sure if the gimbal bearing is camphered or not but i dont believe that this is the problem either. If i remove the rear motor mount bolts then the drive slides in like butter but it pushes the engine forward that inch or two. The input shaft goes into the coupler to the point that i can't see the splines anymore so I assume they are lining up just fine. It seems to be hitting something in the engine coupler. I actually managed to hammer the drive close enough to thread the nuts on the studs but as the drive drew close to the mating surface, everything seems to be binding up. Nuts are very hard to turn, sterndrive becomes resistant to movement, and the engine was lifting off of the front engine mount. What is going on here?!? If the alignment tool slides in so smooth, why wouldn't the drive slide on as well? Any help is more than appreciated. I am at a total loss....
 
Measure the length of your old Input shaft and the new one. There are two different length shafts on the earlier boats. Early Inline 6 and V8s had different shafts.
 
Just a note....If you cannot push the drive right up to the bell housing by hand or with a little push, SOME THING IS WRONG! Never pull the drive on with the Nuts.
 
Thanks for the advise docksidemarine. I knew that there were a long and short shaft, but this "old style" long shaft is news to me. I knew that the resistance wasn't right. Thats why I stopped and am in search of answers. I dont have the old shaft to measure the difference but I will measure the new shaft a.s.a.p. and if it is the 9-9/16" then I will assume that I need the 8-1/8". Thanks again everyone for all the helpful advise. I will update shortly.
 
Sure sounds like the input shaft is a tad longer than the origional....... Time to break out the measuring stick, if you still have the old one in hand.
 
Thanks everyone for all the help! It was the input yoke. Got ahold of the 8 1/8" and everything slid together like cake... Now I have a new problem though, of course. Water in my oil with a new head gasket and new manifold gasket... Any ideas?
 
Found a crack in the manifold. Water leaking out of the water jacket into the exhaust ports on manifold. Could this be how the water is getting in the oil?? The intake ports on head seem to be saturated with oil... What is going on here!? Any help is greatly appreciated. Thanks (Btw- Sorry that this is posted in mercruiser sterndrive forum. I didn't see a mercruiser engine forum.) Thanks again
 
I live in southern california. Cold for us is 60degrees... I dont think it froze up. What I don't understand is how the water gets from the exhaust to the oil pan. Even if the manifold leaks into the exhaust, wouldn't it just blow out the back? The engine has a small turbo on it as well, incase it makes any difference... Thanks again for the advice, I'm at a total loss.
 
greichert1 said:
I live in southern california. Cold for us is 60degrees... I dont think it froze up. What I don't understand is how the water gets from the exhaust to the oil pan. Even if the manifold leaks into the exhaust, wouldn't it just blow out the back? The engine has a small turbo on it as well, incase it makes any difference... Thanks again for the advice, I'm at a total loss.
Click to expand...

Ayuh,... What motor is it,..??

Water would have to seep past the rings for the exhaust water to end up in the oil,...
I'd sooner think that boat hasn't Always lived in Southern Cal, 'n the block is frost cracked...
 
Thanks everyone for all the help. The motor is a 72' mercruiser 3.0. I believe that I am getting major blow-by becuase the vent tube ontop of the valve cover is blowing out a pretty good amount of air when running so i'm hoping the water did just seep past the rings... Even with the water in the oil and cracked manifold AND blow-by, it still runs pretty damn good so i'm hoping the engine is salvageable. If its a cracked block i'm just gonna have to walk away from it. I have more money in it than its worth already. Thanks again everyone for all the advice, I wouldn't have even gotten this far without you guys!
 
Ok, so heres the update... I pressure tested the engine cooling system(with head on) and it seems to hold just fine. A new manifold costs close to what the boat is worth so i decided to try jb-weld on the crack first. The jb-weld seems to be holding up well and the manifold now holds pressure. I once again put everything back together with new gaskets and oil. Fired it up today just to get milky oil once again! If the water jackets all seem to be holding pressure, then where could the water be coming from? The exhaust ports are now bone dry where they were filling with water before. The intake ports are once again soaked with what looks to be oil. I am at a loss here... I cant afford to just buy a new engine. Does anyone have any ideas what could be going on here? Thanks for any input.
 
It appears that you are going to have to bite the bullet and get a reliable manifold. Try eBay but you need them to garauntee it is not cracked.
 
Thanks for the quick response. Yeah, thats basicly where I am headed next. I found a new one on Ebay thats pretty reasonable. But the question is... If the manifold is holding pressure when I do a cooling system test, then should I spring for the new manifold? I dont understand how and where the water is getting in the oil... Thanks again for all the help.
 
I put the manifold back on the engine loosly(no bolts) and hooked the water lines back up. I plugged the 1" line, coming out of the back of the turbo, (that dumps into the exhaust elbow) and plugged the 3/4" inlet that goes to the sterndrive. I made a pressure tester out of a brass T, a vacuum gauge, a valve stem and some automotive tubing(since its a raw cooling system and has no radiator to test with standard cooling pressure tester). I hooked the pressure tester up to one of the 3/8" lines coming off the T-stat housing and pumped it up to around 15psi. All water jackets including block, head, manifold, and turbo should be pressurised and there is no leak down... How else could water be getting in?
 
Heat will cause a crack to expand........... the best way to find out if you have a water leak is to use a somke tester.

Seal off all outgoing water IE, the exhaust ebow real weel and introduce the smoke into the incomming water hose and see if it comes out the same place as the valve cover vent/pcv. where you see the excessive blow by now.

If smoke comes out there then you have a water/cooling system leak........................

Maybe crank the pressure to 30-50 psi and see what happens?
 
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