Yamaha 2hp - cooling dismantling queries

LittleSister

LittleSister

Well-Known Member
Joined
12 Nov 2007
Messages
20,379
Location
Me Norfolk/Suffolk border - Boat Deben & Southwold
Visit site
I have an aged Yamaha 2B, which I haven't used for several years but now want to put back into service. It starts and runs very nicely, but there is barely any cooling water flow. As there is some flow I assume it is not the impeller, but the typical problem of passageways caked up with salt and limescale.

I have read a number of threads on here about such things, and seen a video on You-Tube, which talk about removing the engine to clear the passageways either side of the plate between the engine block and the leg. I have no manual and have as yet been unable to find one on the net. I have very little time and even less patience, so I don't want to embark on a serious strip down of the outboard. If I can't fix it easily it will have to go to someone who knows what they are doing (though heaven knows where, how or when).

Can anyone advise me whether I can lift the motor off the leg (held on with 6 bolts, it seems) without either -
a) dismantling the leg itself, or
b) dismantling the engine itelf (several people talk about removing the head, but I'm not clear if they're talking about the cylinder head, or the power head, i.e. the whole engine).

Also, if the gaskets beween the motor/plate/leg need replacing, can they just be made using paper or somesuch?
 
LittleSister said:
I have an aged Yamaha 2B, which I haven't used for several years but now want to put back into service. It starts and runs very nicely, but there is barely any cooling water flow. As there is some flow I assume it is not the impeller, but the typical problem of passageways caked up with salt and limescale.

I have read a number of threads on here about such things, and seen a video on You-Tube, which talk about removing the engine to clear the passageways either side of the plate between the engine block and the leg. I have no manual and have as yet been unable to find one on the net. I have very little time and even less patience, so I don't want to embark on a serious strip down of the outboard. If I can't fix it easily it will have to go to someone who knows what they are doing (though heaven knows where, how or when).

Can anyone advise me whether I can lift the motor off the leg (held on with 6 bolts, it seems) without either -
a) dismantling the leg itself, or
b) dismantling the engine itelf (several people talk about removing the head, but I'm not clear if they're talking about the cylinder head, or the power head, i.e. the whole engine).

Also, if the gaskets beween the motor/plate/leg need replacing, can they just be made using paper or somesuch?
Click to expand...


You may find a PDF version of the manual on the web (or a CD version for peanuts on Ebay)
It's not that difficult to dismantle and clean up. You will find the labyrinth at the base of the motor unit partly clogged, and also the passages in the cylinder head, with salty deposits.
They can be dug out with stiff wire and fresh water hose.
New gaskets are worth the effort, under £20. They are asbestos based I recall - so take care.
I've done the job on a pontoon with about 4 tools so don't be put off!!
 
Thanks for the replies, but the specific information I'm still after is

LittleSister said:
Can I lift the motor off the leg without either -
a) dismantling the leg itself, or
b) dismantling the engine itelf (several people talk about removing the head, but I'm not clear if they're talking about the cylinder head, or the power head, i.e. the whole engine).
Click to expand...
 
LittleSister said:
Thanks for the replies, but the specific information I'm still after is
Click to expand...

The powerhead can come off complete from the leg. The head does mean the cylinder head. Take care, as its very easy to break bolts and strip threads - the alloy is soft, and the s/s bolts can be stubborn.
 
I have two of these engines, one working that I bought at a boat jumble for £120 that I stripped down and cleaned all the water ways and one I brought for £139 not running that I'm about to rebuild, get proper gaskets cost about £29. Impeller about £8. The engine is easy to take apart, getting the shaft off can be hard work, it has a square socket that is just a tapered push on fit, grease that well before assembly. The head can be done on its own but to clear all the water ways you need to do a full strip, the plate under the engine has water ways in it, the water pipe can be cleaned by just pushing a long knitting needle up it, it has a square rubber block on the top which pushes in to a slot. When you undo the 6 bolts under the plate you will find you cannot just drop the leg down, you will have to take of prop, remove the circlip on the end of the shaft and washer, there is more but that will get you going, I will keep a look out for your posts if you have a further question. Took me quite a why all the first time about 6 hrs due to problems getting the shaft off, once all cleaned up with new gaskets about 4hrs to rebuild, the hole for the gearbox oil is so small that I filled the gearbox before putting the prop back on.
 
Different question but still on the same basic engine (2B). It runs well but has now developed a slight leak from the water jacket to the outside. This became evident after I had bought and fitted a new impeller plus casing. Is there some inexpensive way whereby I can plug this?

I am thinking of using a Dremel type tool to remove the corroded alloy and then applying epoxy putty to rebuild the opening. Any thoughts are much appreciated.

TIA.
 
PuffTheMagicDragon said:
Different question but still on the same basic engine (2B). It runs well but has now developed a slight leak from the water jacket to the outside. This became evident after I had bought and fitted a new impeller plus casing. Is there some inexpensive way whereby I can plug this?

I am thinking of using a Dremel type tool to remove the corroded alloy and then applying epoxy putty to rebuild the opening. Any thoughts are much appreciated.

TIA.
Click to expand...

I havedone this on several engine , boken pull start mounting on top of a 8 hp honda, hole throught to valve gear still good after 14 years(Chemical metal). corroded gearbox on suzuki dt40, gearbox oil slight leakout water in, epoxy 3 layers was still working after 4 years , the one enging had some really heavy use running regularly running 12/15hrs at a time .pair of engins sold now did tell buyer about the repair ! Corroded casting on honda water pump feed casing allowed exhaust to be sucked into water pump , still working after 10 years , I cannot believe how thin the casting is at that place . I have used putty but always seems to stiff to work so I prefer chemical metal (edit its polyester though) it always seem to stick better . Cleanliness is next to godliness if you want it to stick forever!

http://www.henkel.co.uk/2838_UKE_HTML.htm?nodeid=8802703015937
 
Last edited:
You must log in or register to reply here.

Share this page

Top