Evinrude 140 service - part 3 the Impeller. How to get the gearcase off?

rich222 · 02 July 2020, 15:38

Ok, having got the motor to run and the steering freed up, I am now trying to get into gearcase to check the water impeller.

I've taken all the necessary bolts out, including that sneaky one up under the trim tab plate.

The lower section is hanging on like grim death.

It is moving slightly side to side and I've got a gap at the prop end of about 2mm but no gap at the transome end.

I am pretty sure there are no other fixings, so I am guessing that someone siliconed the gearcase to the mid section or its just full of aluminium corrosion.

Do I just keep on applying more leverage?

(yes the shifter rod is disconnected)

I've done smaller outboards before they usually seperate easily. This is big and old and hasn't been split for at least 6 years...

Nos4r2 · 02 July 2020, 16:38

Oh dear, I bet this is an old V4?

I think you may find the powerhead and driveshaft splines are rusted together.

davej · 02 July 2020, 16:44

Common problem with old O\B, I shouldn't think its been siliconed, its just lots of bi metal corrosion between Alu casting and SS studs, wooden wedges, lots of plus gas and wiggling. The other tack is careful application of heat from a gas torch. However, it could be that the driveshaft is stuck at the top end where it fits into the bottom of the crank/powerhead. That can be a more difficult problem and a mate of mine I think hung his whole motor upside down and feed in plusgas down the driveshaft and eventually it released but he did have enough space to feed it in. You should be able to find some demo stuff on youtube. I think the 'Dangar Marine' guy renovated an old 140 OMC and put loads of youtube clips about it. Good luck.

rich222 · 02 July 2020, 16:59

Quote:

Originally Posted by Nos4r2

Oh dear, I bet this is an old V4?

I think you may find the powerhead and driveshaft splines are rusted together.

Yes was wondering if the drive shaft was stuck... The top end is nice and clean and free of corrosion from what I can see. The gearcase is well crusty!

spartacus · 02 July 2020, 17:02

I'd avoid levering it with anything metal - as you'll likely damage the cast alloy leg. If you have a rubber mallet, then get that on it and hammer around the anti-cavitation plate. Important: if this drops, you can lose a toe, so get some wood blocks under the skeg ready to catch the weight when it gives way. Trim the engine all the way down so gravity is on your side.

I've read a few forums so they suggest putting the bolts back in, just enough thread to catch it when it goes. Stick muffs on it and fire it up. Hopefully the vibration will shake it free.

Another option is to drive wooden wedges (a bit like door jams) in at a couple of key places.

Interesting video here on a 40hp. Not practical in your case.

https://www.youtube.com/watch?v=10D-xmcWQbs

Peter_C · 02 July 2020, 22:48

Get the gap at the back as open as possible inserting a wedge. Then insert two wedges at the middle of case and remove the back wedge. Now pull the lower unit backwards trying to open the front gap up. If you can get any movement keep going doing the same thing. You might be able to slide under the trailer, and kick just above the skeg backwards.

Try not to scratch the paint, but if it requires using metal pry bars so be it.

rich222 · 03 July 2020, 10:07

Quote:

Originally Posted by Peter_C

Get the gap at the back as open as possible inserting a wedge. Then insert two wedges at the middle of case and remove the back wedge. Now pull the lower unit backwards trying to open the front gap up. If you can get any movement keep going doing the same thing. You might be able to slide under the trailer, and kick just above the skeg backwards.

Try not to scratch the paint, but if it requires using metal pry bars so be it.

Paint? what paint?

It's opening up, slowly, but not getting any easier.

I'm just wary of forcing it too hard and breaking something.

It feels like its under tension as it still wants to spring back together.

Is there no means of getting at the other end of the drive shaft, without stripping the entire motor? If not, do I just keep going?

Should I keep going with wedges or try harder impacts on the anti-cav plate (using a wooden buffer)?

Other options appear to be inverting the whole motor (not that easy, it's a big bugger) or as a last resort, cut a hole in the leg, get in there with a hacksaw, cut the drive shaft in half, then remove the bits and replace with new. Bung hole!

Nasher · 03 July 2020, 10:23

Quote:

Originally Posted by Nos4r2

Oh dear, I bet this is an old V4?

I think you may find the powerhead and driveshaft splines are rusted together.

I'd like to bet this is your issue.

Been there, done that!

I was lucky enough to get mine off by doing the below, but it will depend on how long it's been like that.

Put the engine in gear and jam a lump of wood between the prop and cav plate.
Leave your current decorating tools in place as wedges, you may as well now they are there but wood is less likely to damage the casting.

Take the plugs out of the engine and rock the flywheel backwards and forwards, which may, if there is any wear in the splines, free it off.

If not, I seem to remember Nos tieing the engine to an Artic and pulling the case off with a forklift!

Nasher.

rich222 · 03 July 2020, 12:03

Success!!! I have beaten the Evinrude beast once again...

2 hours of very careful prying with wedges and off it popped - well gudgingly slid.

As you can see, no lube what so ever on the splines. Rust and no o-ring to be seen.

Casings made it with no damage other than the flakey paint.

Now to check the impeller.

I watched a video of a guy in a boatyard hammering the hell out of an outboard that looked almost new. I think I got off lightly.

Thanks for all your help and moral support. So glad I didn't break anything.

rich222 · 03 July 2020, 13:00

Impeller is actually not too bad. The plates have grooves near the centre.

Not 100% sure on the water seal around the drive shaft. Looks a bit deformed.

The seal to the water pipe isn't too great either.

So I have a complete water pump kit on the way.

Nasher · 03 July 2020, 13:22

Well done.

Plenty of grease on re-assembly and drop it off every 6 months to clean it up and keep that rust at bay.

Nasher.

spartacus · 03 July 2020, 16:20

Good news.

That water pump doesn't look like it's been apart in years.

paintman · 04 July 2020, 10:40

Are the waterpump housing bolts on this torqued in inch/lbs? Don't confuse with ft/lbs!

I seem to recall reading somewhere that when greasing the splined end you should avoid getting grease on top of the shaft or it will make getting it all bolted up again difficult as the grease won't compress or easily squeeze out?

davej · 05 July 2020, 07:22

Well done, just drop it at least yearly and it will be fine, yes to not putting a grease blob on the top of the drive shaft. It would be great to see some pics posted when you have it running.

Dave

rich222 · 05 July 2020, 10:57

Right, another question!

I've just put a hose onto the water pipe that leads up to the motor from the water pump.

Still no sign of any water at the tell tale.

There is water coming from a hole (a drilled hole) at the base of the motor, where the water pipe enters, I can see it looking up inside the mid section.

I assume this is a pressure relief of some sort so I am assuming there is some sort of valve thats stuck between the water pump and the thermostats?

I don't want to take the thermostat covers off, unless I really have to, as I'll have to get new gaskets etc.

I am assuming that the tell tale should run all the time, not just when the thermostats open... That would be pretty dumb!

Does the motor need to be turning to allow water up into it?

(edit)

The poor service manual has a water flow diagram which omits the tell tale and the 'aspiration' valve. It also omits the hole where my water is coming out from. It's a truely usless diagram! As is the 'aspirator' diagram that has no description or labels on it at all. It appears to have just been put in as an afterthought.

The 'aspirator' is a valve that opens at 2000rpm and appears to route water from the thermostat to the tell tale above 2000rpm and routes water from the exhaust housing to the thermostats below 2000rpm...

rich222 · 05 July 2020, 12:42

Success!

Not 100% if I just wans't waiting long enough or there was a blockage or the aspirator was stuck.

Gave the throttle a good waggle back and forth - the aspirator valve is attached directly to the carb linkages.

Took off a small pipe that runs from the block to the aspirator valve and I could hear air escaping.

Eventually water has appeared at the tell tale.

Amazing how much water is in there, when you take the hose off.

Now I just need to get it to run for more than 2 seconds.

Will start a new post about that!

Nos4r2 · 07 July 2020, 10:10

Quote:

Originally Posted by Nasher

If not, I seem to remember Nos tieing the engine to an Artic and pulling the case off with a forklift!

Nasher.

Nope, it was a Frontera in low range and a Rover 400. It dragged the car with all 4 wheels locked and the case still didn't budge. Was an ancient Merc blueband though and it'd been together for years.

I use a tiny bit of ACF 50 Corrosion block grease on the join now, it doesn't harden and dry out like others.