More o/b problems - Yamaha Malta

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davidej

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I have just changed the impellor and as the water passage in the lower part of the leg feeding the pump was blocked, I removed the small casting which is immediately below the pump to enable me to clean it properly. When I lifted this off, the gear selector rod came out as well.

I have now reassembled it and run the engine. Water flow is fine, but the gear selection is reversed ie neutral gives forward and visa versa.

This gear selector rod has a sort of crank at the bottom and, as far as I can make out, this operates some sort of lever connected to the drive dogs. I assume I have not got the two parts engaged properly.

Can anyone suggest where to go from here or point me to a downloadable workshop manual.
 
The only thing I can think of is that you have reconnected the upper and lower sections of the shift rod incorrectly .
I.e. too much overlap or not enough overlap. Not familiar with it so dont know which. Not overlapped enough I think. Should have marked it I think before disconnecting.

Not possible to refit the lower section back into the gearbox 180° out is it?

What Hp and year is it ?
 
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I am pretty sure the rod is the right way round. It sort of curves forward at the bottom . I tried it the otherway round and didnt seem to engage at all. Also there is not much room for error with the clamp.

I feel the problem must be where the curved bit engages the the part that actuates the dogs. Should I think of taking out the bottom gear and dogs- presumably by loosening the two set screws immediately above and below where the propshaft emerges.

Some sort of exploded diagram would be useful!
 
The year letter should tell you the year but now I have found two totally different keys to the letters :confused:

I cannot find any info for a 3.5 though .

3 hp models have forward and neutral gears, 4 hp have reverse as well so a I guess its going to be pretty similar to the 3hp models

Diagrams are here, but only really for models imported to the US. http://www.boats.net/parts/search/Yamaha/Outboard/parts.html

I'd not dismantle anything you did not previously.

I think I'd slacken the shift rod clamp. Move the lower section until its in neutral. Put the lever in the neutral position as well then do the clamp up.

May need a bit of fine adjusting to get it to engage forward properly.

Maybe you'll have to do it the other way. Get it in forward, put the lever in forward and then do the clamp up.
 
VicS said:
The year letter should tell you the year but now I have found two totally different keys to the letters :confused:

I cannot find any info for a 3.5 though .

3 hp models have forward and neutral gears, 4 hp have reverse as well so a I guess its going to be pretty similar to the 3hp models

Diagrams are here, but only really for models imported to the US. http://www.boats.net/parts/search/Yamaha/Outboard/parts.html

I'd not dismantle anything you did not previously.

I think I'd slacken the shift rod clamp. Move the lower section until its in neutral. Put the lever in the neutral position as well then do the clamp up.

May need a bit of fine adjusting to get it to engage forward properly.

Maybe you'll have to do it the other way. Get it in forward, put the lever in forward and then do the clamp up.
Click to expand...

Assuming your Malta is a Neutral/Forward only model then Vic is absolutley correct. Having done this myself I know exactly what you mean! The good news is that you can carry out the fiddly operation of getting the gear selector clamp in place by trial and error through the hole in the leg once you remove the rubber grommet (I always used to wonder what it was for until I changed the impellor). All I can say is that when the shift rod goes to neutral it seems to slacken off a little and when in drive almost needs "pulling in". Sorry for the rubbish descriptions but that's how it felt to me. You will know when it's right!
 
Thanks to Vic S and emsworthy for their suggestions but I am still stumped.

It is a 6L5K model and can't find that one on the US website. It just has neutral/forward gear change.

It appears to change with a very satisfying clunk. Also I have looked at the clamp joint which you get at thru the grommet and there is no real room for error. I compared it with another malta and they look identical - with the clamp as far down on the upper rod as is possible, there is a washer rivetted on the end to stop the clamp dropping off. The lower rod has about 1/4 in showing above the clamp.

I continue to beleive that I did not re-insert the lower rod into the bottom gear housing correctly. However I tied it several times and the result seemed the same. I suppose if all fails, I may disassemble it and try again.
 
Are you sure the the problem is as you describe? Are you moving the selctor and then turning the prop by hand?
On the Evinrude 4hp I recently rebuilt it gave all the indications of being wrong, but it turned out that the mechanism relied on the motor running to effect the change of gear.

In that case it is the rod interfering with a coil spring concentric with the output shaft.
Vic has found a diagram which suggests that isn't the case on your motor, but it is till worth trying it under load on a boat before getting too involved. It may be the mechanism relies on the pressure exerted by the prop to effect the change. Worth a try.
 
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Lakesailor said:
Are you sure the the problem is as you describe? Are you moving the selctor and then turning the prop by hand?
On the Evinrude 4hp I recently rebuilt it gave all the indications of being wrong, but it turned out that the mechanism relied on the motor running to effect the change of gear.

In that case it is the rod interfering with a coil spring concentric with the output shaft. The spring has a tang which sticks up and the rod engages it, this opens the spring and pushes the dog into engagement . If the motor isn't running it won't work. If it is really working backwards way-on and uses a similar mechanism, perhaps you have got the rod on the wrong side of the tang on the spring.
You may need to dismantle the output shaft as you suggest to see this. But don't rush to do it until you have determined that may be the problem. It isn't much of a job, but lots of outboards never get re-assembled after frustration sets in.
Click to expand...

No I dont think its anything like that OMC one of yours at all. I remember your photos of that. Mind you I cannot figure out what is wrong if the two halves of the shift rod cannot be adjusted to sort it out.

Quite confident that the shift rod bears on a plunger in the inner end of the prop shaft and that operates the clutch dog. All the 3 hp Yammies seem to be the same but cannot find a 3.5 hp on the Boats.net website

look a t this page.

The shift rod and gear lever are on the engine controls diagram
 
Another page shows the shift rod alignment.
It also shows a spring pin bearing on the side of the bottom part of the rod. Did that go walk-about? It may only be to reduce vibration, but it may play a part in aligning the rod properly.
 
Lakesailor said:
Another page shows the shift rod alignment.
It also shows a spring pin bearing on the side of the bottom part of the rod. Did that go walk-about? It may only be to reduce vibration, but it may play a part in aligning the rod properly.
Click to expand...

Good call
I don't know what that is
Well worth investigating

I reckon as you suggest it will align the rod correctly ... stop it twisting before its clamped to the top half.

Still cannot understand how neutral and forward have gotten the wrong way round.
 
Lakesailor said:
Another page shows the shift rod alignment.
It also shows a spring pin bearing on the side of the bottom part of the rod. Did that go walk-about? It may only be to reduce vibration, but it may play a part in aligning the rod properly.
Click to expand...

This is the most useful diagram to date. It clearly shows the shift rod (part 38) which is what I inadvertantly removed. It is not terribly clear, but it looks as though the crank in that rod points backwards. When I got in a muddle, I asked the dealer which supplied the impellor which way it should go, and he said with the crank forwards.

When I get a moment, I may strip it down and try the rod the other way round. Unfortunately the diagram relating to the lower gearbox doesn't seem to have any shift mecahism so I can't see how the rod engages at the bottom to actuate the dog.

The pin (part40) is still there.

To the contributer who asked this, I only noticed the shift was reversed when I started it in a tank to check the water was pumping properly.


Thanks for all your help - will keep you posted.
 
davidej said:
This is the most useful diagram to date. It clearly shows the shift rod (part 38) which is what I inadvertantly removed. It is not terribly clear, but it looks as though the crank in that rod points backwards. When I got in a muddle, I asked the dealer which supplied the impellor which way it should go, and he said with the crank forwards.

When I get a moment, I may strip it down and try the rod the other way round. Unfortunately the diagram relating to the lower gearbox doesn't seem to have any shift mecahism so I can't see how the rod engages at the bottom to actuate the dog.

The pin (part40) is still there.

To the contributer who asked this, I only noticed the shift was reversed when I started it in a tank to check the water was pumping properly.


Thanks for all your help - will keep you posted.
Click to expand...

The diagram is available from the link I posted way back in the thread!


the shift mechanism is shown in This diagram ( that is also available from the link I posted earlier! )
The shift rod operates the plunger #42 that in turn moves the dog #43 in or out ( against the pressure of the spring #41) of engagement with the gear #39

.
 
I think the rod is reversed.
I just drew two diagarma one (1) with the rod facing forwards and one (2) facing back wards. If you push the rod down in the first the pin moves aft
If you push the rod down in the second the pin moves forward.
The extra movement is accounted for by the spring.
 
So you are saying that when moving the gear lever to the neutral position and thereby moving the rod down, if the cranked part is facing forward the plunger will move aft ( further into the shaft ) and disengage the clutch dog.

That's how I figure it. It means that the cranked part should face forward, which is the opposite of how it appears in the diagram but how the dealer says it should be fitted.
 
I'm sorry boys- I hold my hand up!

The rod was 180 degrees out.

In my defense, I was told to put it with the crank forward by an Authorised dealer and putting what I now know is the correct was didnt seem to engage properly.

I have never looked at the bottom gears of an O/B and was expecting something like a car gearbox with dogs and a lever so I didnt recognise this plunger as being the mechanism.

Thank you again --all's well that ends well!
 
I have never looked at the bottom gears of an O/B and was expecting something like a car gearbox with dogs and a lever so I didnt recognise this plunger as being the mechanism.
Click to expand...

Glad its all sorted. I am surprised it was possible to fit the rod the wrong way round but it was one the the questions two of us asked right at the start!

Lots of different ways outboard gearboxes work. None much like car gear boxes. This is one. LS has described how it worked on his 4hp Evinrude. My 6hp Evinrude has similar plunger mechanism but a totally different dog clutch. Some have a lever system that moves the dog clutch some have balls instead of a dog clutch.

OMC have used at least two different electrical shift systems as well as hydraulically assisted systems

And that's only the few variations i know about.


We can turn our collective attention to Orion50's MD11C now!
 
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davidej said:
I'm sorry boys- I hold my hand up!

The rod was 180 degrees out.

In my defense, I was told to put it with the crank forward by an Authorised dealer and putting what I now know is the correct was didnt seem to engage properly.

I have never looked at the bottom gears of an O/B and was expecting something like a car gearbox with dogs and a lever so I didnt recognise this plunger as being the mechanism.

Thank you again --all's well that ends well!
Click to expand...

Glad to hear that it is back in operation again.
 
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