Yamaha 2B: What look for?

[Goldie]

I need a light o/b for ease of transport and have an option on a Yamaha 2B which looks to be in vgc and is recently serviced with carb clean, new impeller and plug. Is there anything in particular I need to check on? How much water flow/tell tale should I expect on an engine this small, full flow or steady trickle?

Viewing first thing Saturday!

Thanks in anticipation.

 

[steve66]

You should get a spray of water from the relief holes...listen for any bearing noise. Nice little engines. Remember to flush it in fresh water

 

[VicS]

I need a light o/b for ease of transport and have an option on a Yamaha 2B which looks to be in vgc and is recently serviced with carb clean, new impeller and plug. Is there anything in particular I need to check on? How much water flow/tell tale should I expect on an engine this small, full flow or steady trickle?

Viewing first thing Saturday!

Thanks in anticipation.

Inspect the overall condition.
ask to see it started from cold and run in a barrel

The 2B does not have a telltale as such but you should see some water being blown out of the exhaust back pressure relief port on the back of the "leg" together with some exhaust gas.

Make sure it runs evenly with no signs of any misfiring.

 

[Goldie]

Thanks gentlemen. The barrel is arranged and I’ve asked for the engine not to be started before my arrival. The info on what to expect re water flow is really useful. As you may guess, this isn’t an engine I’m familiar with!

 

[anoccasionalyachtsman]

If it's in fine fettle it should start on the first or second pull from cold, and with the slightest tug from warm.

 

[Fantasie 19]

Does this help..?

 

[Rappey]

They weight a whole 9.8kg and are easy to take apart when needing repair.
The faults I have found -
The impellor sits in a stainless cap. The aluminium housing oxidises, expands and crushes the thin stainless cap squashing the impellor. Fairly easy to fix without cost.
The water coolant pipe enters the Base of the engine with a rubber seal. This shrinks? So water flow around engine decreases, leading to overheating. New seal and it's fixed.
Final issue, shafts seal where shafts enters engine. Once worn the spinning motion pulls water into crank case. Engine runs fine until it's stopped. Then crank bearings rust.
£12 from bearing specialist and a new seal and it's fixed.
I would buy another if one comes along at a great price

 

[Goldie]

They weight a whole 9.8kg and are easy to take apart when needing repair.
The faults I have found -
The impellor sits in a stainless cap. The aluminium housing oxidises, expands and crushes the thin stainless cap squashing the impellor. Fairly easy to fix without cost.
The water coolant pipe enters the Base of the engine with a rubber seal. This shrinks? So water flow around engine decreases, leading to overheating. New seal and it's fixed.
Final issue, shafts seal where shafts enters engine. Once worn the spinning motion pulls water into crank case. Engine runs fine until it's stopped. Then crank bearings rust.
£12 from bearing specialist and a new seal and it's fixed.
I would buy another if one comes along at a great price

More really useful info, thanks. The vendor (private sale but ex Yamaha tech selling on behalf of retiring relative) mentioned the impeller housing oxidisation issue and tells me that this one is good. Waterways have been cleaned out, new head gasket, plug, ultrasonic carb clean etc etc. Started first time from cold, ran evenly and picked up smoothly. It all looks in ‘almost new’ condition with very few marks indeed. Did I buy it? You bet I did!

Thanks for all the really useful inputs gents.

 

[Rappey]

Blocked waterways was not a problem I ever encountered.
Impellor housing - you lever out stainless housing, scrape away excess expanded aluminium around it , give it a coating of duralac and it should be good for many more years.

 

[anoccasionalyachtsman]

Blocked waterways was not a problem I ever encountered.
Impellor housing - you lever out stainless housing, scrape away excess expanded aluminium around it , give it a coating of duralac and it should be good for many more years.

You're probably diligent about flushing. The PO of mine wasn't: the head channels were almost completely solid.

 

[Rappey]

I'm very guilty of not flushing ?
Have had many larger 2nd hand outboards on the back of boats on swinging moorings that have never seen fresh water but have also never had cooling problems.
Same with inboard diesel heat exchangers. Guess I'm just very lucky ?
My 2hp yamaha suffered all I mentioned but who knows how many hrs it had run ?
It was getting a little hot so I dismantled it and found the rubber seal between cooling pipe from impellor and engine was in a bad way allowing a lot of the cooling water to go back down the leg and not pumping impellor around the engine.
It's still in a bucket of bits 5 yrs later in my shed as I found a still in its box 10 yr old tohatsu 3.5 for crazy cheap money.
Nothing beats the lightness of the yam 2 though.

 

[anoccasionalyachtsman]

I'm very guilty of not flushing ?
Have had many larger 2nd hand outboards on the back of boats on swinging moorings that have never seen fresh water but have also never had cooling problems.
Same with inboard diesel heat exchangers. Guess I'm just very lucky ?

I'm not that good either, but it occurs to me that its orientation as it cools is probably a big factor. Mine would have been lain on its side probably head down, so a perfect way to clog it. Vertical or cocked up is probably the best way to drain it.

 

[Rappey]

its orientation

I was actually thinking that as I typed my previous post but then thought nah...
But now you mention it, I beach the dingy , remove outboard and it stands up while i put the dingy away ,carry the engine for barely 2 mins then it gets stood up in my shed until it's next needed.
With bigger outboards I leave them down after turning off whilst I put everything away ,put on covers etc.
The last thing I do is raise outboard.
Does it really help?

 

[anoccasionalyachtsman]

I was actually thinking that as I typed my previous post but then thought nah...
But now you mention it, I beach the dingy , remove outboard and it stands up while i put the dingy away ,carry the engine for barely 2 mins then it gets stood up in my shed until it's next needed.
With bigger outboards I leave them down after turning off whilst I put everything away ,put on covers etc.
The last thing I do is raise outboard.
Does it really help?

No idea, but I love a good hypothesis.