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Lower unit / driveshaft stuck in powerhead

W

Waverider17

New member
Hi Everyone,

It's service time for my 1989 Merc 60hp, same time every year for the past 5 years, I prepare for the half hour job of pulling the lower unit to change the impeller but from what I can tell the driveshaft has welded itself to the powerhead. I can get about half an inch gap with wedges and that's taken 3 hours but it won't shift more than that without the feeling that something's going to break. Has anybody got any suggestions? Will I damage the gearbox if I put too much tension on the driveshaft? I wish I could get some penetrating oil up in the splines but there's no access unless I start drilling! Any help greatly appreciated as always.
 
I live in saltwater Florida and have done many of these, luckily only a few stuck that bad. My best approach was instead of trying to remove the gearcase, was to pull the powerhead, you have precise tension with the use of an engine hoist with the proper lift ring, alowing you to pull, stop, wait, repeat, soak with PB blaster or some other solvent. It will come off, just take your time and nothing will break. Which engine is this? The cross flow or looper 60HP?
 
I believe it's a cross flow, serial OB240262. I've got a lifting ring, but no hoist, being determined though this may be my opportunity to invest. Is it a labour intensive job to pull the powerhead? Can't say I've tackled one before.
 
Actually it is very easy assuming no corrosions issues. OB240 is a crossflow. All it will cost you is a new powerhead base gasket. You can get a folding hoist from Harbor Freight for cheap.
 
Thanks for the advice, I'll have a look at my manual. It's just finding the time with only a few weeks before I put the boat on its mooring. I'm sure the impeller would go another season but there'd be a whole lot more corrosion around the driveshaft splines to add to the headache!
 
The last time you did the impeller, did you re-install the small black neoprene O ring on the driveshaft, on top of the waterpump housing? That keeps water from spiraling up the driveshaft and invading the splines, that can be the cause of the corrosion. Also you must grease those splines to keep them from twisting and welding to the crankshaft.
 
I can honestly say that I did all of the above which is why I'm scratching my head. I thought I'd missed a bolt at first but counted 5, albeit with 2 that can't be removed fully until the lower unit drops some more. It's moored in freshwater but used a lot out at sea for 6 or 7 months and then stored on its trailer for the winter.
 
That doesn't sound like fun, I think Im about to go through the same process. I was think of making some kind of clamped platforms out of timber to create two flat surfaces to distribute the load evenly and jack them apart with a small hydraulic bottle jack.
 
It's just such a pain, I've kept it well serviced and everything lubricated with marine grease. I've had older salty lower units apart that haven't seen an impeller change for years! I haven't got time this close to the season to attempt to lift the power head so was contemplating drilling a hole in the leg with hope to get access with a straw to give the splines a good soaking with penetrating oil but I don't want to drill in the wrong place. That or fix a ground anchor below the outboard and use ratchet straps to try and separate. I could be wrong but I just don't feel like I should be putting that much force on something that's connected to the gearbox.
 
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