Yamaha 2hp outboard/impeller change

Incidentally.. anyone reading this thread who might be able to tell me what the recommended replacement sparkplug is for this engine?
The one that came in mine is unreadable.. can't figure out the brand or read any numbers on it...
 
vidapura said:
Incidentally.. anyone reading this thread who might be able to tell me what the recommended replacement sparkplug is for this engine?
The one that came in mine is unreadable.. can't figure out the brand or read any numbers on it...
Click to expand...

NGK BR5HS gapped at 0.6 - 0.7mm
 
In view of all the helpful advice here - and Vidapura's pep talk - I had to man up and go back to this. And it came free! As said, to get the lower leg to come off both the drive shaft and the tube that it sits in have to come free up at the head, and the cooling water tube needs to come away down at the water pump. All are push fit connections - it's just been many years since anyone push fitted them. Once the lower leg was off the rest came apart easy, so I have my broken piece of circlip and can see that the impeller is in a decent state but worth changing having come this far. The upper parts of the drive shaft have plenty of surface rust - worth painting perhaps?

Flushed with success I removed the leg from the head and can honestly say that no water was ever going to push its way through that accumulation of salt and grit. The worst of it is now out and I'll have a go with some descaler too. Then it'll be a big spare parts order for all the washers and gaskets before attempting reassembly. Thanks to all the contributors - what did we do before the internet? Hopefully I'll be able to report back later on a sweetly renovated engine but there may be some intermediate questions on reassembly to post before then!
 
Ahh thats brilliant Bomber !!
heh heh.. thrilled for you.

Now you need all the replacements ... I got a kit of spares off ebay .. all the gaskets as well as the impeller...
Round 30 quid.

By the by, getting the foot back on the leg is a frustrating job.
Juggling the driveshaft and that water tube while trying to get a bolt in.... have to admit I did turn the air blue a few times...
Basically you need to get that water tube shoved as far down into the water pump gasket as possible.. bout an inch.. which isn't easy cos the gasket is grippy...

I did it with the head back on so the water pipe couldn't get away up the top end.. and then squeezed it all together at the foot with clamps before putting the bolts into the foot.
Helps heaps if you have the engine mounted on something solid too btw. ( plank of wood stuck in the bench-vice)

The clamps I got in lidl.. but they look like this:
http://www.rockler.com/irwin-quick-grip-6-in-mini-bar-clamps-2-pack

And just so you know.. it took me about 4 days to figure my way through all this the first time.. so you're doing grand.
 
vidapura said:
Ahh thats brilliant Bomber !!
heh heh.. thrilled for you.

Now you need all the replacements ... I got a kit of spares off ebay .. all the gaskets as well as the impeller...
Round 30 quid.

By the by, getting the foot back on the leg is a frustrating job.
Juggling the driveshaft and that water tube while trying to get a bolt in.... have to admit I did turn the air blue a few times...
Basically you need to get that water tube shoved as far down into the water pump gasket as possible.. bout an inch.. which isn't easy cos the gasket is grippy...

I did it with the head back on so the water pipe couldn't get away up the top end.. and then squeezed it all together at the foot with clamps before putting the bolts into the foot.
Helps heaps if you have the engine mounted on something solid too btw. ( plank of wood stuck in the bench-vice)

The clamps I got in lidl.. but they look like this:
http://www.rockler.com/irwin-quick-grip-6-in-mini-bar-clamps-2-pack

And just so you know.. it took me about 4 days to figure my way through all this the first time.. so you're doing grand.
Click to expand...

The water tube /leg re-fitting is a PITA. However, having got all this apart, replace all disturbed seals, including those both ends of the water tube. You may lose water internally if you don't. Also before refitting the driveshaft square end - clean up well and apply copper coat grease to the fitting. If it needs to come apart again - it will be easier!
 
Hi, I am following in the footsteps of many who have gone before attempting to solve the problem of a pathetic flow of water from my Yamaha 2B. Although I have read the whole of this thread I feel in need of reassurance. Apart from the water issue I feel the 2B is remarkable little engine and I do not wish to cause it any harm.

So I have removed the 2 bolts in the lower leg/foot and the foot dropped 1mm. Having read and understood all that is holding it now are the push fit connections of the drive shaft and tube (at the top of the leg just under the engine) and the water tube (at the bottom of the leg/just above the foot) I made a device. I measured the width of the casting between the top flange of the foot and the bulb that is the gear box. I then cut a slot (about 22mm wide x 70mm long) in a piece of 150mm x 25mm x 600mm long hardwood which with the engine securely mounted I can slot this wood over the gearbox and clout the lump of wood with increasingly larger hammers until the force overcomes the compression of the shaft and tubes.

So far the gap has increased to 6mm and I have noted that 3 retaining studs have come free so that when I turn the foot round the flywheel also turns.

I note the link posted earlier in this thread is no longer working.

I have also tested the 6 bolts on the underside of the engine, just turned them one quarter turn just to see if they are free.

My options seem to be get a bigger hammer or take the 6 bolts out to see where this gets me??????????

Look forward to advice

Thanks

Mike
 
Mike

There’s nothing unusual about the difficulties you’re having - I knew an outboard engineer who refused to attempt servicing on engines that hadn’t had the lower leg removed for 5 years because they sieze in place...

Until you’ve got it in pieces it can be difficult to understand how the units connect together. You have probably downloaded the parts diagrams so I’m using their terminology in the descriptions below.

With the lower leg bolts out and the ‘Dowel Pins’ (the retaining studs you refer to) free the lower leg is still being held in place by the push fit interfaces between
1) the top of the 'Drive Shaft' and the bottom of the lower 'Crank 2' shaft
2) the top of the 'Upper Casing Gasket' tube and the 'Exhaust Guide', or the bottom of the Upper Casing Gasket tube and the 'Water Pump Housing Cover' - it shouldn't matter which of these come apart
3) the 'Water Tube' and the Water Pump Housing Cover

It is probably worth attempting to remove the Power Head from the Upper Casing by undoing the 6 bolts you tested, but interfaces 1 and 2 from above will still need to come free for these parts to separate. You just need to keep trying and if like me you have already removed the 'Pinion’ gear from the Drive Shaft then your attempts so far will have bent the water pump’s ‘Outer Plate’ so now you have to continue.

When you do get it all apart you may find that the water pump and impeller weren’t the main problem anyway - my old 2B was completely blocked by scale around the Exhaust Guide at the top of the Upper Leg, and the engine block/Cylinder Head. Most of this is relatively easy to scrape out once you’ve separated the Power Head from the Upper Leg/Exhaust Guide - though I was anxious about removing a Cylinder Head for the first time in my life.

I have many pictures of my 2B in pieces but disappointingly they're still not ideal for your problem. I've attached the most useful below. The first is the top of the Upper Leg (with the Water Tube in place but the Drive Shaft and its Upper Casing Gasket tube already removed). The second is looking at the underside of the Power Head showing the lower Crank Shaft protruding - this is most likely rusted into the top of your Drive Shaft. The third is the cleaned up underside of the Exhaust Guide - the Upper Casing Gasket tube pushes into the round hole on the left and is likely to be a tight fit.

IMG_0332.jpgIMG_0333.jpgIMG_0341.jpg

Hope at least some of this is useful and the best of luck.

Peter
 
Hello Peter,

Thanks for taking the time.

I have not removed the pinion gear from the drive shaft. Should I have done?.

Have not removed prop. Should I have done?.

I have only removed the 2 bolts in the lower leg and given it a few taps with a hammer & the piece of timber with the slot cut into it.

I only use the outboard to get to my boat which is about 500 metres / 10 minutes . I have been wondering whether I really need to worry about the cooling for such a short journey?. Could be tempted to bolt the thing back together and try it.

Mike
 
MINESAPINT2 said:
Hello Peter,

Thanks for taking the time.

I have not removed the pinion gear from the drive shaft. Should I have done?.

Have not removed prop. Should I have done?.

I have only removed the 2 bolts in the lower leg and given it a few taps with a hammer & the piece of timber with the slot cut into it.

I only use the outboard to get to my boat which is about 500 metres / 10 minutes . I have been wondering whether I really need to worry about the cooling for such a short journey?. Could be tempted to bolt the thing back together and try it.

Mike
Click to expand...

Hi Mike
The driveshaft tube has seized onto the impeller housing..Its a common issue. I do have a spare exhaust plate, driveshaft tube and impeller housing If it does end up breaking or has to be cut
 
Mike

I don't believe removing the Pinion gear will help - it just means that as you attempt to hammer the Lower Leg off, the little peg in the Drive Shaft that turns the impeller will bend the top of Water Pump Outer Plate. I think you're better off leaving the Pinion in place.

Removing the prop will make no difference - it only makes getting at one of the bolts in the lower leg easier, but you've already done them.

I have no experience of how long you can run the engine with limited cooling. You could remove the Cylinder Head (four bolts surrounding the spark plug) to inspect and clean the water channels around the engine block - this will also give you an indication of how badly blocked they are likely to be around the areas shown in my photos too. You would be able to pour some descaler in to try and clear them too, but I found this of limited benefit.

My engine repairs have become more of a learning experience as I decided to move the boat to a pontoon berth before they were completed. It sounds like you rely on the little 2B more so it's a difficult call whether you should push on or quit now to avoid potential damage. Amazingly there was a never used NOS Yammy 2B on Ebay the other week for around £500...

Peter
 
I have very similar Mariner engine. After reading this thread, I got lost. Can I remove the leg without removing drive shaft first? It seams as there is insert only connection on drive shaft?
Also, can I test flow in the head simply by blowing to the water pipe?
 
Well, removing gearbox went well. 5 minutes and done. Unfortunetely, one of bolts holding impeller broke... I wonder if I will be able to remove it (well, somehow I will...). What type of bolt it can be metric, or imperial? If I fail to remove it, can I just drill it and use one bolt - in this case it would be beneficial to use 'liquid' gasket?

On the other side, I tried to blow into cooper pipe. There is some resistance, although feels that flow is fine. I wonder if I can give it a good flush, since engine is anyway in pieces now. Maybe hot water? Should I use some descaler? Or some home-chemical substance?
 
Well it sounds like you have it all apart even if there has been a little collateral damage as a result of the age of the parts. In your position I would try an adhesive sealant and the single bolt. Once set and all the lower leg is back together you can test how effectively it pumps by immersing the lower part of the assembly in a bucket and putting an electric screwdriver into the top of the drive shaft to spin it.

Getting some descaler into the cooling channels may well improve matters - especially if your tests so far indicate that there is at least a route around that means the descaler will be able to get in there. Got to worth a try if it avoids further disassembly with risk of breakages and the requirement for new gaskets.
 
Oh boy... I finally managed to remove impeller and it does not look good... Metal housing is bend inside and does not like to come out. I put leg to freezer so it will shrink and maybe will go out. Looks like I need to buy (expensive) full repair kit. Or I could reuse current one, but probably after straightening it won't work anyway.....
 
Hi, please someone managed to remove
slawosz said:
Oh boy... I finally managed to remove impeller and it does not look good... Metal housing is bend inside and does not like to come out. I put leg to freezer so it will shrink and maybe will go out. Looks like I need to buy (expensive) full repair kit. Or I could reuse current one, but probably after straightening it won't work anyway.....
Click to expand...
Hi, please did you managed to remove that metal housing around impeller? I managed to fairly "squash it" around the sides but still pretty stiff and sitting in there...
Thank you.
 
Lukasx said:
Hi, please someone managed to remove

Hi, please did you managed to remove that metal housing around impeller? I managed to fairly "squash it" around the sides but still pretty stiff and sitting in there...
Thank you.
Click to expand...
Some time ago, but I think I did. I can see I have bought housing on ebay around the time I have wrote that post. I guess patience goes a long way. Probably you can also drill the bottom slighytly so there would be a pull points.

slawosz said:
I put leg to freezer
Click to expand...
This and my ebay history just scrolled. My marriage had no chance :ROFLMAO::ROFLMAO::ROFLMAO:
 
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