Yamaha 2a - cooling help

[livewire]

I came by this outboard which was siezed and neglected.



I got it moving and stripped the carb and electrical systems. It now sparks and spins very well.

Thought i'd better check the cooling side of things, blew compressed air up the water inlet pipe. Nothing, so took the head off. I found the water jacket full of white crud. I've cleaned it all out but i cannot find how the water circulates??



I then took the powerhead off to look for the water outlet as i had read that it exits down the leg with the exhaust.



Nothing there either, does anyone know or have any ideas?

[Keith.P]

I have one of them, it runs, but its still neglected.
I have no use for it, but I think my one's a Mariner, it's still the same as a Yamaha, I think.

I would block the inlet hole and fill the waterways up with limescale remover, all that white stuff.
Also if a manual is needed, I think I have all the Mariner manuals.

[Horsley-Anarak]

Yam is the same as mariner.

You will need to drop the gearbox off and have a look at the impellor.

You were lucky the drive shaft was not rusted to the crank, both of mine were (2bs not 2A), as that makes it almost impossible to get the gearbox off without damaging something.

They are a great engine, very light, carry one handed. The later 2b engines sell for a couple of hundred on the bay.

H-A

[phil]

Try blowing compressed air into the triangular shaped hole in the center of the photo, I assume that is the water inlet, feel for where the air exits the power head, of course the cylinder deck water passages will need to be blocked now that the head is off.

[livewire]

I have one of them, it runs, but its still neglected.
I have no use for it, but I think my one's a Mariner, it's still the same as a Yamaha, I think.

I would block the inlet hole and fill the waterways up with limescale remover, all that white stuff.
Also if a manual is needed, I think I have all the Mariner manuals.

Yes it is the same as the Mariner/Mercury 2hp one of the same era.

I scraped and ground the white stuff out very easily, but cannot see any route for the water.

A manual would be great as i couldn't find much info on the internet about these little engines.

[livewire]

Yam is the same as mariner.

You will need to drop the gearbox off and have a look at the impellor.

You were lucky the drive shaft was not rusted to the crank, both of mine were (2bs not 2A), as that makes it almost impossible to get the gearbox off without damaging something.

They are a great engine, very light, carry one handed. The later 2b engines sell for a couple of hundred on the bay.

H-A

I have dropped the gearbox off, your right it wasn't easy. I used a skin knife to open the gap at first once i had undone the gearbox attatching bolts. Then slowly got something wider in and eased it off from there. It was a fight but i done it without breaking anything.

Now the driveshaft is stuck fast to the gearbox end, i want a long metal rod to drop down the inside of the driveshaft to seperate the two. But i haven't a long metal rod yet.

It is such a light engine as could be a good aux engine to carry. But my OCD is screaming out and if i get this sorted i'll be after the engine cowling next. If anyone see's one around.

[livewire]

Try blowing compressed air into the triangular shaped hole in the center of the photo, I assume that is the water inlet, feel for where the air exits the power head, of course the cylinder deck water passages will need to be blocked now that the head is off.

You are correct, the triangular shaped hole in the centre left of the underside of the power head is the water inlet.

This feeds to the small slotted hole at the top centre of the photo, this feeds straight into the water jacket around the piston. But from there i can't see an outlet??

If i used compressed air it doesn't go anywhere, just builds up preassure.

[phil]

Must come out somewhere in the chamber that contains the exhaust port or the connected small chamber at center top right side, try poking around with a thin screwdriver, perhaps it's covered by carbon backed with lime scale.

How about a photo of the top of the leg. Is the oval hole at the bottom of the photo open to the exhaust port chamber or not, it's hard to tell.

[livewire]

Good idea Phil, i'll work backwards. So to speak.

I cleaned the bottom of the engine off but i didn't find anything.

I because of what you said i looked at the bottom of the leg, looking carfully i found a hole!



Then when i looked at the bottom of the power head i found a hole that matched.



I never noticed this hole before as it didn't show anysign of being a waterway and looked more like a bolt hole. So i had to take the plate of the bottom of the powerhead.



Now this hole was blocked solid, i drilled it out and now it seems sorted. Very happy now. Now i need to buy some gasket paper for the bottom of the engine.

Has anyone got a cowling laying around for one of these? Maybe i need to do a separate thread.

Thanks for your help so far.

[phil]

That's great! Glad you got it.

[mick r]

Hi,

Have manual on my computer.

PM me if you still need one, and I will load to CD and post to you.

Regards,
mickmick r
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