Yamaha 2hp lower housing removal

[simonfrancis]

I have a Yamaha 2hp which has been utterly reliable despite being maintained infrequently (never!) apart for regular use and fresh water flushing.
I have not used it for a year or two since buying a Yam Malta and now it is very stiff to turn over and won't start... i suspect there is some salt water corrosion.
I want to remove the gearbox housing/water-pump etc a job that I have just done easily on the Malta. The problem I have is that the gearbox won't shift apart from a millimetre or two.
If I open the gearbox housing up and remove the cir-clip on the bevel gear then it moves a little further as the shaft recedes into the gear, but stops again, I suspect as the waterpump is preventing any further movement.

Apart from the bolts holding on the gearbox is there anything else that i need to dismantle to get the box off the leg?

I suspect that the Drive shaft is seized into the crankshaft and that is why I can't shift it.

Any advice welcomed, thanks
Simon

 

[VicS]

l'd think you are right about the drive shaft being stuck in the crankshaft and about the water pump preventing the drive shaft from being pulled from the gear case.

You don't say how old, but I don't think they changed much over the years,. If not too old you should be able to find an exploded diagram

at http://www.yamaha-motor.com/outboard/parts/home.aspx

or http://www.boats.net/parts/search/Yamaha/Outboard/parts.html

Perhaps you can turn it up-side-down and get some good release oil (eg Plus gas .. not a water displacing fluid like WD40) to the crucial area.

If the engine is stiff to turn over then maybe get some oil into the cylinder to soak down around the piston rings and into the crank case via the carb to soak into the bearings

Was not fogged after last use I suppose.. just abandoned in a corner

Run on 100:1 mixture too? That does not leave enough oil behind to protect the insides.

 

[alahol2]

When I lowered mine, the drive shaft came with it. ie the drive shaft detached from the head unit. There is also a cooling water pipe that pushes into a rubber grommet in the lower unit. I never did manage to get the drive shaft off the lower unit (it seems a bit fragile, thin walled) but I was able to check the state of the impellor, which was OK. So I just put it back together

Just found the instructions... http://www.inadee.co.uk/marineroutboard.htm

 

[grafozz]

I recently rebuilt the waterpump on my 2hp yam . when you remove the prop and lower face housing you will see the splined driveshaft entering the housing from above . on the end of this is a very small circlip . remove this and you will be able pull off the gears then tease the lower housing off .its fiddly , but be gentle with it all and it will part . whilst in there it is a good idea to either rebuild the pump , kit is £62 or just replace the impeller . These were the lightest 2 strokes made and mine is 12 years old and still runs very well . good luck ,gramos.