Now that I've loosened all 5 nuts, I try and wiggle the whole lower unit up n down to see if it is going to drop easey!

We drop the lower unit about a quarter inch onto the loosened nuts!

Once there, we remove the two front side nuts and the rear nut leaving the two middle nuts to support it!

If it won't come down - well you have the option of a rubber mallet tapping on the top of the rear extended Fin of the lower unit, or softwood like pine with a hammer gently tapping the wood!

If you can get just a crack of movement you can insert tapered wooden wedges and tap them in slowly gently with a hammer to get it to drop onto those nuts! The aim is to NOT damage the alloy housing with anything hard made of steel!

OK..

Now we have it dropped about 5mm or 6mm and hanging on those two center nuts on each side, it is time to avtually pull the lower unit!

I support the lower unit (a second persons real handy at this stage!)and remove the two remaining nuts!

Then wiggling the lower unit up 'n down gently,I work the long drive shaft out thru the bushes inside the leg.

You can get 'hung up' doing this!

The long drive shaft, is turned down in diameter on a lathe,except for two spots where it runs inside these two bushes inside the leg!

One of the bush spots is just above the waterpump housing down near the gear case and the other is just below the top spline! These spots are polished and full diameter of the driveshaft!

You have to pull these two spots thru the two bushes inside the leg which are a tight fit! If you don't keep the pull direction aligned - you can get the shoulder of the drive shaft below the two bush spots jammed in the bush making pulling very difficult. Just again wiggle the whole lower unit up n down gentlyand "feel" your way thri the two bushes and the whole lower unit will come away in your hands!

You can see one of these polished full diameter sections of the drive shaft in the picture below - it is just above the black plastic water pump housing!

Place the lower unit down on something that will support it's weight and not damage the skeg, vent plates etc! (I use an old tyre)!

If you look up insde the leg once you have the lower unit pulled..

You will see the lower of the two bushes you have to pull that polished full diameter drive shaft section thru!

Theres nothing scarey up in there to be afraid of - if you pull that lower unit and wiggle it a bit you will get it out!

Sacrificial anode!

While I have the lower unit out I like to clean up my sacrificial anode!

If this anode is really chewed away then of course you should replace it, on this occasion I think mine just needs a good clean!

So - once removed (just one thru bolt with a nylock nut to remove)

I get the two halves and dump them into a bucket or jar of Pepsi for a half hour or so!!

This makes me fizz up like crazy! What it does is dissolve all the salts where they have been corroding away for months at a time if your boat stays n the water!

Once they have stiopped fzzing and dissiolved all the salts, I then 'grind them' (in this case on the concrete driveway!). They are a soft Zinc alloy (Called Hydral or Mercatel in this case, being Mercury legs on Honda outboards)!

I grind each face back to nice clean shiny metal ready to go back into service for another 3 - 6 months!

Next time they will be replaced!

So - once ground - wash them and re install them!

Now it's time to open up this water pump housing!

Undo the 4 bolts holding the water pump housing together, and slide the top half containing the stainles insert and impeller up the long drive shaft, and turn over in your hand!

OK,

We are now 'flying blind' coz dummy here forgot to take the photo's of this next step!

Pull out the impeller from it's housing!

When you turned it over the impeller looking at you is the bottom face of the impeller!! You will note it has a long slot inside the centre hole...that does NOT run all the way thru to the other side - almost but not all the way!

This slot accomodates the 'woodruff key' which should still be sitting in it's machined channel in the drive shaft!

If you turn this impeller over - you will see the upper face does not show the woddruff key slot.

It's important when we install the new impeller to remember the slot for the woodriff key goes down over the woodruff key as we slide that housing back into place!

We can inspect our old impeller for signs of any imminent failure!

If you lok closely where the fingers pointing you'll see the beginnings of rubber craks which can be a sign of impending impekller failure due to perishing of the rubber impeller fingers where they flex as the pump rotates inside it's off centre housing, which is how the pump sucks and pushes it's water to keep your engine cool!

You cannot afford to leave an impeller in a OB until it fails - because you will overheat and ruin your engine! They should be replaced periodicaly IMHO every 100 hours or 12 months...

Some manufacturers (no names no packdrill) claim no servicing on a new OB for 3 years or 300 hours, but to my mind thats too long to not replace an impeller!

I like to clean the stainless plate of my water pump housing and the stainles shousing insert itself - all the while looking for any signs of any excessive wear, or bad groves that might allow water to pass the impeller!

Finding non - it's time to insert the new impeller into the housing woddriff key slot face up! (ready to go back ver the shaft and slide down onto the woodruff key!) Again no pics sorry I had both hands full! (Coz the ruvbber impeller is springy and has a mind of it's own wanting to jump back outta the housing!

So - it's somewhat like putting a jumper over a school age kids head when they have a mind of their own and dont want to cooperate!

You'll get it in there - I did!

When you do - make sure the legs bend to face the sanme way the old impeller legs did!

Also rotate the impeller in the same clockwise direction such rthat when you slide the housing back down the drive shaft - the woodriff key will line up with the slot in the impeller!

In order tomake the impeller easey to turn within the housing (and so it is well lubed when you first start up the engine!) I apply a small sliver of grease tothe end of each impeller finger just so it slides easey around the inside of the impeller housing!

So - put it back on sliding down over the woodruff key so that the slot aligns!

Replace the 4 securing bolts for the water pump housing!

I thne stand the lower unit up on it's skeg and rotate the prop in the direction it normally travels when in forward (remember we left it in forward gear at the beginning? now you know why!) ;o)

This helps to get the impleer fingers all into the right spot and allows you to feel for any that might be jammed be beig bent back the wrong way or indeed to feel thah the woddruff key is installed properly and the impelleris turning within the housing correctly!

I should have mentioned I like clean and re-grease the back & front face of the woodruff key and slot across drive shaft before I replace the housing just to help keep any corrosion at bay and to aid easey removal next time!

Your done till step 9!

First thing to do before re-instaling the lower unit is to re-grease the splines! (After you've cleaned em first of course!)

Here you can see the second polished larger diameter section that runs inside a bush inside the leg, just below the spline!

It's important NOT to apply any grease to the TOP of the spline only the sides!

The top of the spline goes up inside a collar on the bottom of the crankshaft! If you put grease on the top of that spline - it can get forced up into the crankshaft and if it can't get out under compression may do damage..(like pushing your crankshaft hard up against it's thrust bearing, - just as bad, it may create a vaccuum up in there stopping you from easily removing the lower unit next time!

So - just grease the sides of the spline please!

Also grease the spline on the gear shift rod please!

I like to apply a thin coating of grease to the whole of both shafts to help protect against corrosion, should you ever do a water pump seal, and end up pressurising the inside of the leg with salt water before your next service!!

I apply a bit more grease to the two spots where the bushes meet the larger diameter polished sections of the shaft!

Bung the lower unit back in where it came out from!

Get a couple nuts on, wiggle it up into place and get the rest of the nuts on and then tighten them in a series pattern so the lower unit pulls evenly up into place!

I like to make a thin coating of grease on the lower unit edges where they mate to the leg before I pull the bolts up tight!

Now pull them up tight!

Ir you have any trouble aligning the gear shift rod, you can actually "move" the sleeved section within the upper leg - by using your fingers in near the steering tube - you can see a section where the shift rod passes in clear view..and jiggle it a little until the lower unit gear shift rod mates nicely with the upper section sleeve!

Before I bung the lower unit back in I apply a little grease to the lower bush and gear shift sleeve! I also apply some to the water tube that goes into the top of the water pump housing!

You can see them in this photo - the water tube at the top - bush in the middle and gear change rod spline receptor sleeve at bottom!

I also clean out the top rubber seal of that water pump housing and lightly grease it with my finger just to make re-insertion of that water tube at the top of the above photo, a little less traumatic to the rubber seal! ;o)

Usually it fits just like a finger in a b.. well er - well you get the idea! grin!

Now it's time to tighten up all those 5 nuts!

You'll see grease ooze out of the joint of the leg / lower unit where you smeared it before re-installing the lower unit, just wipe off with a clean rag after everythings tight!

If you get ANY sort of serious refusal to pull up tight, STOP and remove the lower unit again - check that you have everything right and go again - you should NOT have to force it to fit again it should slide in and nip up tight on the nuts!!

Especially check you do NOT have grease on top of the drive shaft for reasons already mentioned!!

Next job is to hook up the flushing muffs and water and give her a short run to see ir she will pee!

Bewdy - pees like a draught horse after a night on the turps! ;o)

If it don't - you did something wrong!

Look like I got both right coz they both pee like a draught horse!

Cheers!

another great pictorial flywest. this is a great thread ,and thanks to you im sure many of the readers will give it a go.i know i will be helping a mate in the coming weeks change out the impeller on his 75 horse honda ,and will have this thread printed out on paper as a reference .GREAT STUFF!!!!!
cheers mitch

p.s you should write a book .outboard mantenience for the beginner

always in it just the depth that varies

Enjoying and learning some good stuff from these posts Flywest. Thanks.

Esky's Loaded, Boat's Ready...... Lets Go!!!!!!
Top stuff mate, im actually the bloke with the 75 Honda that Mitch will be helping me with!! Really learning a shitload from what your doing.... Luv it!!! Keep em comin Flywest, BRILLIANT.

But I'm havin trouble finding time!

Actually been doing some "security" work for a colleague, static guard patrols etc, p[ounding the pavement for 9 hours at a time, which I'm not used too - have blisters on me feet sore ankles and sore legs etc and keep falling asleep in front a this damn 'puter!

Anyway - In between eating and sleepin and working I've managed to change lower unit oil on both OB's and didn't get one good photo! Damnit!

Also raised both outboards up 3 holes to get the vent plates level with underside of the hull! Again no pics!

I think I can 'fake' the pics tho of these two simple tasks well enough to demonstrate what to do - having now done both! Need to buy some sikaflex tomorrow after another long days patroling to finnish the OB raising job...!

Will try and get more pics uploaded in dys to come - just a little busy right bnow - have a lot on puter and a lot to upload and more to take for a few simple jobs like filters and oil and plugs etc!

The hardest ones done - a few easey ones to follow!

Just coz they are done doesn't mean they can't be better tho if someone else knows what they are doing and wants to add suggestions to improve my methods feel free to speak up please!

I ain't got no mortgage on good ideas - I'm sure lots of you have some of your own bout the best way to do things!!

Cheers!