Need help with Johnson 3.5 hp outboard please

[jerryat]

Hi All,

I've just bought a 2005/2006 s/h Johnson 3.5 outboard (2 -stroke) from long time friends who haven't used it for a couple of years. It is in pristine condition, started second pull, and runs like a sewing machine, BUT, there is very little water coming out of the leg and, more importantly, only the odd drip from the 'pee' hole.

I knew the impeller would probably need changing, but although I have no problem stripping my baby Mariner/Yamaha's down to the bone and reassembling, this model is new to me.

A Google search referenced these forums and produced info that removing the two bolts at the leg/gearbox junction (one facing up, one down) would allow the drive shaft/gearbox etc to be 'pulled clear'.

However, I've tried this, but despite using gentle leverage it doesn't want to move, and I don't want to risk perhaps unnecessary damage to a totally unmarked engine if there is something else I should be doing as well.

So before I add 'grunt' to the leverage, could any of you kind people confirm that this IS the correct method of removing the leg/gearbox assembly to let me get at the imeller housing? I'd be very grateful for any advice.

Many thanks

 

[yoda]

Jerry

I think there may also be a gear linkage to undo which may be behind a large rubber grommet.

Yoda

 

[VicS]

Yes you are going about it in the right way.

BUT you have checked that it is not simply the telltale that is blocked


There are only two screws

The shift rod is in one piece which simply pulls from the gear box and there is no rubber plug!

It is probably the vertical drive shaft that is not pulling away at its top end.
However the drive shaft is in several parts and i am not quite sure where it separates on this model. Immaterial really because its all inaccessible.

More brutal persuasion I think.

Lakesailor may be able to advise if he is around.

Maybe if you turn it upside down you can get some penetrating oil ( eg Plus Gas, not a water displacing fluid like WD40 ) to run down the shaft.
Not sure though if you can get at it via the exhaust outlet or only if you can separate the gearcase slightly.

The bottom end of the shaft is retained in the gear case by a circlip below the pinion ( and in the water pump by the impeller which is keyed to the shaft)

BTW the model number will tell you if it is a 2005 or a 2006 one ( the same anyway I think) the date letters are SO for 2005 and SD for 2006.

Thre are good dagrams at http://www.boats.net/parts/search/BRP/JOHNSON/parts.html

 

[jerryat]

Jerry

I think there may also be a gear linkage to undo which may be behind a large rubber grommet.

Yoda

Hi Neil!

Hope you and yours are well!

Thanks for the info, but there isn't a grommet on this model, i.e. you don't undo a drive shaft clamping bolt halfway down the leg.

Guess it's the hard way or nothing!

Cheers

Jerry

 

[Lakesailor]

Instructions here (This one shows a grommet, but otherwise should be the same)

Yes. A good yucking will move it. If you can mount the transom bracket on something solid with the leg hanging, a piece of 2x2 softwood or similar can be used as a drift with a meaty hammer or better still a mallet. This avoids scratching or damaging the leg, but don't hit on the thin cavitation plate flanges. The bit where the casting flairs around the output shaft is pretty meaty. It's only possible to hit it at one side at a time, but supporting the opposite side with your hand and hitting as downwards as possible seems to do it. Don't knock seven bells out of it. Just some gentle but heavy blows. The alternative is to use an old wide chisel to split the joint, but it will damage the edges of the casting.
Maybe even some heavy blows with the heel of your hand will be enough. (Ouch)

 

[jerryat]

Hi Vic!

Many thanks for your usual very comprehensive reply!

Yep, the first hopeful thing I did when I saw the 'pee' hole drip was to push some flexible wire right up the tube as far as the block, where it couldn't go any further, but no joy I'm afraid.

You are right, there is no rubber grommet, so it does look like like brute force may be the only solution. My major concern was that I might be levering away at the bottom when perhaps the gear lever linkage at the top needed dosconnecting first.

I'm sure you're right that it's the jamming (probably rusting!) together of the drive shaft to the crankshaft that's the problem, so unless I can break that bond I've got a real problem. Once that's clear the impeller/gearbox set up is as you describe and identical to many of the small outboards.

You are also right that the 2005/2006 models are the same - this one was actually bought new mid 2006 - and the parts link you gave was extremely helpful.

Very many thanks Vic and I'll come back, with smiles or tears, to let you and others know how things go! Wish me luck!!

Cheers

Jerry

 

[jerryat]

Wow!! Good morning Lakesailor, thank you for that idea.

So far I have used the blade of a knife to break the initial bond and open up a gap of circa 0.5 - 1.00 mm. I then used a 19mm chisel with a fine edge to try and progress this but got no further increase, which is where I stopped and nibbbled my fingernails up to the elbow!

I've just nipped out to the garage to have another look, so may I just clarlify where it is I should try the softwood/mallet suggestion? Do you mean I should place the timber below the cavitation plate and on the top of the gearbox casing at the point above where the propshaft exits, i.e pretty well on the top bolt which secures the gear case bearing housing?

It does mean the angle is fairly acute and obviously not directly downward, which is what you suggest, but I have got the engine clamped to a piece of 4 x 2 in my massive engineers vice, so it's in a perfect position to try this.

I'll certainly try your method first because as you rightly say, the only other solution is to use chisels or the like and certainly damage at least the edges of the castings.

Thanks Lakesailor for taking the time to reply.

Cheers

Jerry

 

[VicS]

Wish me luck!!

Good luck

Dont worry unduly about any minor damage to the joint faces between the gear case and the leg Its not a water tight joint. You can file down any little burrs. Obviously you don't want to end up with it looking all mangled though.

 

[jerryat]

Hi Vic, Lakesailor, Neil and all those interested!

Well I'm presently wearing an ear-to-ear grin, which will tell you that, after using pretty modest force with four very thin metal wedges, the leg suddenly popped down and out!

There is VERY minor burring in about four places where the two parts meet, but as Vic says, very brief work with a fine file will sort that out in a couple of minutes.

The parts exposed are literally 'as new', and completely spotless, BUT thankfully, the probable culprit was exposed - only two blades left on the unusual three-bladed impeller!

Although I ensured that ALL of the broken blade was accounted for, I wanted to check that the copper water feed tube inside the rest of the leg wasn't blocked in any way, so connected a small bore plastic tube to this and blew through it. By putting my wetted finger over the 'pee' hole, I could produce bubbles, so air at least is getting through. I intend trying to blow water through this when I've finished my well-earned cup of tea!!

So success so far, and very many thanks to all of you for taking the trouble to reply. Having such helpful and positive responses was just what I needed to get over my gibbering trepidation!!

Kind regards

Jerry

 

[VicS]

Good

When you reassemble put a light smear of grease on the offending part of the drive shaft so that next time it will hopefully come apart more easily.

Do the same for all the bolts.

 

[jerryat]

Hi Vic!

Yes, I have always coated any bolts I remove with Blakes seacock grease before reassembly to try and ensure that problems don't occur in the future. It has always worked so far.

I should have mentioned for the benefit of others, that there was no rust, nor any sign of it anywhere on the drive shaft. There is a separate square tubular connecting piece joining the crankshaft to the drive shaft, and this as well as the shaft is in stainless steel.

This approx 90 mm length of tube simply fell out when I inverted the gearbox so wasn't restricting the gearbox removal in any way! Seeing the two sections apart now, I have absolutely no idea why they should stick in the first place, but there you are.

Anyway, hopefully this thread will help others in the future, so thanks again Vic,

Kind regards

Jerry

 

[wotayottie]

Interested it starts second pull. Mine ( similar vintage and condition) is a PITA to start although it doesnt have any prostate problems as yet.

 

[gianenrico]

Hello folks!
Some time has passed since You ended this thread BUT it was very helpful for me.
I have a very faithful 2005 engine which, despite sometime spent upside down in the water, when the donk capsised in tow, Always starts first pull.

I have to change the impeller and encountered a PITA with the 2 bolts uniting lower and middle part of the leg: they broked off their head as I tried to gently unscrew them (to gain better acces I unscrewed without a problem the two holding the gearcase).
So I drilled the 6mm bolts with 2 mm drill and managed to destroy the lower one (I threaded again for 6mm and it is OK), but the upper one, while half destryed, does not die!
As mentioned above, I can detach the stern part of the leg but not the bow one: may be it has to to with the clutch lever in the wrong positio: i check in the wekk end !
Thanks again for the encouragement, I have made a .pdf file with explode views AND Part numbers, ready to send upon request.

 

[ReefMagnet]

Seems to be the norm for these motors. My 2005 was exactly the same and I had to replace the impeller just recently. The two bolts holding the lower unit (gear case) to the leg both sheared at the head. The culprit is the corrosion of the aluminium where the bolt passes through the hole in the part it is retaining. In theory, a good soaking in vinegar would probably help dissolve the corrosion to allow the lower unit to separate, but the method for the impatient is to soak the lot in penetrating oil and drive wedges into the gap between the leg and lower unit. I used paint scrapers to get a gap sufficient to drive an old wood chisel - that had been ground down to have a very shallow wedge angle - into the gap around the general location of the holes. It needed a bit of brute force, but no damage to the edges that couldn't be fixed with a bit of a file occurred. Just be careful of the water pump housing when driving in the wedges. I drove the wedges along the joint so they wouldn't penetrate too far into the housing. Also, make sure that you work the gap around the join so that it remains even.

Once the corrosion lets go, the leg should pop off nicely. To add insult to injury, the remaining bolt stubs should undo - using a pair of vice grips - with humiliating ease.

 

[Lakesailor]

Sometimes boiling water will release the corrosion for an instant fix.

 

[gianenrico]

I'm wondering wether the problem is in the QUALITY of the 6mm bolts used in the factory: they should be UNI, S/S but may it be that the "strenght" of the steel is not up to the job?
The strange thing is that the two bolts holding the gearcase came out without a problem.......

 

[gianenrico]

Done!!
I managed to disassemble lower and intermediate sections.
The lower screw's thread is still fine, won't have to rethread in a larger diameter; the upper's ...is filled by the bolt: this one has been cut a couple of mm above its siege, so now I have to patiently grab-and-unscrew it from the casing....just patience.....
By the way, the water pump is in excellent condition, the reduced flow coming from dirt accumulated in the tine holes of the suction part.......

THANKS AGAIN TO THE RESOURCEFUL SUPPORT!!!!

 

[hubbardbilly]

All, I came across this thread while trying to figure out a problem with my 2006 Johnson 3.5. I had the EXACT same problem with the bolt heads snapping off. After a battle with a torch and some flat-head screwdrivers, the lower unit came off. What a headache! Now I have to get those threaded bolts out of the casing. It's not as easy as I thought.

Anyhow, the reason I even took the lower unit off was to figure out why the shift lever won't move! I can't get it to shift in and out of gear. The handle is just frozen in place and there doesn't appear to be any means of freeing it. There's no access to remove the lever itself. Anybody have any thoughts as to how I could free the frozen shift lever? It's obviously frozen at the top, not in the lower unit.

Thanks!

Billy

 

[gianenrico]

Join the Club!!

Seriously, I have both probs.
Yesterday I managed to destroy the last bit of the lower bolt: in my experience, one should tackle the thing directly with a 5 mm chrome plated drill point, as using 2mm hoping to then enlarge the hole proved, in my experience counterproductive. In fact the slimmer points tend to break as soon as they get 10mm deep into the bolt and hen it is a VERY BIG headache trying to proceed. This probably depends on the fact that a vertical fixed drill was not available to me and the one at the Club could not host the upside-downed engine.
With 5 mm it is rather easy to rethread the holes to 6 mm and, given the abundance of vertical alloy, it is possible to lenghten the hoel to 3.5 / 4 cm, ensuring a good closure.

As per the clutch lever, I' m still puzzled over it: once opened the lower unit, a thin s/s lever appears, going up insidde the leg, BUT IT STILL IS HARD to command by the clutch lever. Apparently it should be possible to remove the lever by unbolting (again???? Brrrr!!!!) it from the opposite side.


Hey, let's keep in touch on this!

Best whishes, good luck & cheers!!

 

[gianenrico]

H E L P!!
The engine was assembled with new bolts re-threaded and as usual started on second pull.
BUT the tell tale flow of water was minimal, so back in the basement, reopen the foot, spray wd40 in the output hole and after a while check and see that the flow oround the engine head is free, so change the impeller.
NOW: how to remove the old impeller from the engine shaft? Just inserting a flat blade between the foot lower body and the impeller? Or is it there any other trick? TKS very much for any operational advice.