Yamaha Malta

[anoccasionalyachtsman]

So that's three of us with six of them. Does that make us an owners club?

 

[Boathook]

So that's three of us with six of them. Does that make us an owners club?

A closed one at present !

 

[Sandro]

Thank you QBhoy.

Thank you Boathook for the pictures. Very interesting and useful for my project, as well as your remarks.

I had not noticed the overflow indent in RH channel (always picture in post 4).

I am trying to understand why Yamaha made the telltale hole in the RH channel instead of symmetrically in the LH channel.

If the passages in the head/cilinder were choked the water would continue running from the telltale not giving any warning, and it would not reach the LH channel nor cool the motor, wereas a telltale hole in this position, downstream to the cooling passages, would report the real situation.

On the other hand if Yamaha put the hole where it is they would have had their reasons. But which?

Can you see any?

Here is another (free) link to a part diagram for the Malta:

https://www. megazip.net/zapchasti-dlya-lodochnyh-motorov

Sandro

 

[Boathook]

Thank you QBhoy.

Thank you Boathook for the pictures. Very interesting and useful for my project, as well as your remarks.

I had not noticed the overflow indent in RH channel (always picture in post 4).

I am trying to understand why Yamaha made the telltale hole in the RH channel instead of symmetrically in the LH channel.

If the passages in the head/cilinder were choked the water would continue running from the telltale not giving any warning, and it would not reach the LH channel nor cool the motor, wereas a telltale hole in this position, downstream to the cooling passages, would report the real situation.

On the other hand if Yamaha put the hole where it is they would have had their reasons. But which?

Can you see any?

Here is another (free) link to a part diagram for the Malta:

https://www. megazip.net/zapchasti-dlya-lodochnyh-motorov

Sandro

Until the resurrection of this thread I hadn't given much thought to the cooling! The LH channel is free flow into the exhaust so a telltale wouldn't really work. The harder the engine works the more water goes into the exhaust to keep it cool I suspect. The telltale is only really to say that the water pump is working.
Try putting the engine into freshwater without the thermosat and cover in place and just pull the starter cord. The water very quickly overflows this on a single pull if the pump is working well. When the engine is actually working the water flow must be quite considerable and the exhaust gases quite hot.
When I reassemble I lightly grease the bolts for future removal. I do the same for gaskets apart from the cylinder head one.
More I think about it the engine is well designed and built. All it needs for my dinghy is a slightly shorter shaft ..... but I not getting rid of it!

 

[VicS]

I am trying to understand why Yamaha made the telltale hole in the RH channel instead of symmetrically in the LH channel.

Sandro

Outboard tell tales usually only indicate that the pump is delivering water to the power head They tap off from some point quite early in the cooling system , which is why normally the water peeing is only slightly warmed at most

Large outboards have temperature sensors which will shut an engine off or maybe reduce it to "limp mode" if it overheats.

 

[anoccasionalyachtsman]

I added a tell tale hole to my 2hp Mariner by drilling into the outflow channel for this very reason. On that engine anyawy there is enough pressure left in the channel to give a good dribble.

I'd do the same on a non-pee Malta (and might well change mine because as I said above, those immaculately clean channels in my pic gave no hint that the head was almost completely blocked) and if the flow wasn't conclusive at idle it almost certainly would with rev rise as Vic says.

Don't go too big on the hole though - the water going down the leg 'may' be factored in to exhaust gas cooling, don't want your transoms melting.

 

[Sandro]

Boathook, why give away a better information, if you can know that pump is working AND water is running through the head/cylinder? If there is a good flow the indent is a water flow choke enough to increase back pressure in the LH passage to supply the telltale. Anoccasionalyachtsman tells that it is so also in his 2hp Mariner.


I don’t think that a telltale would steal too much water from the exhaust cooling effect. In Seagull OB, except some very old models, no water at all is conveyed in the exhaust tube. You can feel it if you unadvertently grab a just stopped motor by the exhaust tube.

Time ago I did the pump check by the thermostat: the gush is impressive. Agree on the Malta quality.

Vic, not always; in Seagulls (it might have been already noticed I am a fan of) for instance, telltale and water discharge after circulation around the cylinder are one thing, and are a good indicator of engine working temperature.

Anoccasionalyachtsman, I think to understand that you are favourable to my idea of a telltale hole in the LH channel, just before the delivery into the leg. In this picture (thank you Boathook) the bottom big arrow is where I plan to drill a 2.5 mm hole.



The tube-like boss marked by the top smaller arrow could contain the water channel from cylinder to basement.

If nobody will shout to me for some reason “for the sake of Heaven don’t do that!”, as soon as it will be possible I’ll go where boat and OB are ant tackle this project.

Sometime the thougth comes to me that we could be crazy being here discussing our little boat or engine problems and making projects for the future whilst the world is upset. But then I think that it is right.

As far as we do all what is in our power to prevent being infected or infecting someone else, what can or should we do? Talking boats and thinking to the future as usually helps spending a prisoner’s time (we are rightly confined in home and so you will be soon) and avoiding pessimism taking place, wich is always negative.

So let’s hope for the best and keep on solving our boat owner’s big problems.

Best wishes

Sandro

 

[QBhoy]

You can defo do this modification. Many have already.
although I’m pretty certain this is one of the best small outboards ever made (and see an increase in value every time I look) it would be nice to see a tell tale. As mentioned, I have a fully running older one with no tell tale and 90% of a much newer one that has a tell tale. The newer one has something wrong with the exhaust line in the mid section. I plan to use the top end of the newer one with the lower section of the old one. Just so I can have a tell tale. Haha.
great engines. Also have 2 Yamaha 8hp 2 strokes. What a thing they are and are serious money money now.
also worth a mention is another engine I have. Perhaps an unlikely candidate but the wee 2.2 Suzuki 2 stroke I have is an incredible thing. Literally one hand carry job down the jetty. Alas, no tell tale though !!

 

[Sandro]

Thank you QBhoy for your encouragement.
I am curious: what can be wrong in an exhaust in the mid section? Which are the symptoms?

From what I read in the forum and elsewere it seems that old 2strokes are more reliable than new 4 strokes. I suspect that the difference is not due to the type of thermodynamic cycle but planely to the age of designing and manufacturing, most about designing.
Those engines were designed -and made- for lasting. They did not include planned obsolescence.
Of course it's our fault as buyers to choose a cheap disposable thingy instead of an expensive durable good machine but not always we are given the choice.
My impression can be due to my being an old grumpy chap, but...

Sandro

 

[anoccasionalyachtsman]

You can defo do this modification. Many have already.
although I’m pretty certain this is one of the best small outboards ever made (and see an increase in value every time I look) it would be nice to see a tell tale. As mentioned, I have a fully running older one with no tell tale and 90% of a much newer one that has a tell tale. The newer one has something wrong with the exhaust line in the mid section. I plan to use the top end of the newer one with the lower section of the old one. Just so I can have a tell tale. Haha.
great engines. Also have 2 Yamaha 8hp 2 strokes. What a thing they are and are serious money money now.
also worth a mention is another engine I have. Perhaps an unlikely candidate but the wee 2.2 Suzuki 2 stroke I have is an incredible thing. Literally one hand carry job down the jetty. Alas, no tell tale though !!

Little hole here on your Suzuki and you can have a tell tale on that too. (This is exhaust side and so tells me that water's getting everywhere).

 

[West Coast]

Thanks for the tips in this thread - has given me the incentive to take my Malta apart to inspect and clean the water passages!

 

[davidej]

I've got one as well. It is currently giving me a bit of trouble getting it to run reliable.

I am awaiting some fuel tubing before I start fiddling with it..

Mine doesn't have a pee hole - should I drill one?

 

[anoccasionalyachtsman]

I've got one as well. It is currently giving me a bit of trouble getting it to run reliable.

I am awaiting some fuel tubing before I start fiddling with it..

Mine doesn't have a pee hole - should I drill one?

The only problem I've ever had with them is having to clean out the carburettor, so that would be my first suggestion.

Yes to the tell-tale, and I'd go for the exhaust-side option that we've discussed above. (I'm changing mine over to that side).

 

[Boathook]

I've got one as well. It is currently giving me a bit of trouble getting it to run reliable.

I am awaiting some fuel tubing before I start fiddling with it..

Mine doesn't have a pee hole - should I drill one?

Normally the main jet has a blockage. This can be very difficult to see so try and use a magnifying glass. There is also sometimes a filter in the fuel tap if fuel is not flowing well.

 

[QBhoy]

Thank you QBhoy for your encouragement.
I am curious: what can be wrong in an exhaust in the mid section? Which are the symptoms?

From what I read in the forum and elsewere it seems that old 2strokes are more reliable than new 4 strokes. I suspect that the difference is not due to the type of thermodynamic cycle but planely to the age of designing and manufacturing, most about designing.
Those engines were designed -and made- for lasting. They did not include planned obsolescence.
Of course it's our fault as buyers to choose a cheap disposable thingy instead of an expensive durable good machine but not always we are given the choice.
My impression can be due to my being an old grumpy chap, but...

Sandro

Sandro

I’m not sure what happened to it to be honest. I’ll go look at it now, but corrosion on the tube internally rings a bell.

 

[QBhoy]

This should help you loads. You can see exactly where the water routes are here. This is the later model that has the tell tale

 

[DownWest]

So that's three of us with six of them. Does that make us an owners club?

One more Malta 2.5 owner here. Lovely little motor, bought it off a forumit last year.
Going back to the original question, I would drill a small hole into the ally where the gear lever shaft goes through, then dribble some decent releasing oil into it, gently moving the lever after a bit, then keep dribbling and moving, until it was free.
BTW, plus one about the older O/Bs being better engineered. I have a 3.5 Suzuki from way back, got it seized but with not much use. Blocked waterways caused the bore to distort and the piston didn't like that. Had it gently bored true and now putting it back together. Quality of build is way better than more recent stuff.

 

[QBhoy]

One more Malta 2.5 owner here. Lovely little motor, bought it off a forumit last year.
Going back to the original question, I would drill a small hole into the ally where the gear lever shaft goes through, then dribble some decent releasing oil into it, gently moving the lever after a bit, then keep dribbling and moving, until it was free.
BTW, plus one about the older O/Bs being better engineered. I have a 3.5 Suzuki from way back, got it seized but with not much use. Blocked waterways caused the bore to distort and the piston didn't like that. Had it gently bored true and now putting it back together. Quality of build is way better than more recent stuff.

Great wee things. Actually 3hp they put out and some have suggested the reality is a little more. Much larger displacement than your average 3/3.5hp for sure. Plenty of torque in them for what they are.

 

[anoccasionalyachtsman]

This should help you loads. You can see exactly where the water routes are here. This is the later model that has the tell tale

That's almost as it left the factory compared to my 2nd engine... and only one snapped bolt - you weren't really trying!

 

[Sandro]

Thank you for the picture. It's always good to know what one will find if I ever will have to disassemble the motor.
I hope mine is less salted than some pictures in this thread, as it has been used mostly in fresh water.
Also my main jet got blocked. It looks like it has to do with nowadays (again!) petrol. I always stop the motor by shutting the tap and starving it. I apologise if with this phrase I could start a fierce arguing on doing that or not. I hope i would not; in more than one forum all has been said, denied, prooved, negated on this choice.
About Malta power, when new to me I also had the impression of more thrust in comparison to my previous Johnson 4hp 2st .
Having the approval of the honourable "Yamaha Malta Owners Association", when and if it will be possible to move, I'll go and make the peeing hole.

I made a few modifications to my Malta and others are in view, but this is another story.

Sandro