Puzzling Drive Problem

[Dockhead]

Originally Posted by atoll

had this problem before when the gearbox oil has many hours on it.

the first thing i would do is to drain out the suspect oil and replace with a know brand of the correct oil as specified by mfg.

could be you have been sold "fake" oil,that is infact a chinese or indian counterfeit product,made from old filtered oil.

Branded Mobil oil, sold at Halfords and used with success in the main engine and genset. Do you think fake oil gets onto Halford shelves? eek.

OK, so this is now two different voices saying that oil problems (overfilling; overused) can cause the cluthes not to grip. Good, very good. Since the problem corresponds to my changing the oil and overfilling it, this gives hope. I will first try lowering the level, then changing it again.

Thanks!!!


And thanks to Cal40John for the link to the manual. I have a few electronic versions of this manual, but this is the first with real text in the PDF rather than an image file which can't be searched.

According to this version of the manual:

KM4A, KMH4AAPI Classification .............. CC or higher
SAE Viscosity.................... #20 or #30(not available multi grade)

I think by "not available multi grade" they mean that if 20W or 30W is not available, you can use multi-grade. This is also encouraging.

[sigmasailor]

What is the type of transmission you have?
Some types of Yanmar are known to slip after a mere 500 hours; just Google 'yanmar sd 50 slip'.

[atoll]

Originally Posted by Dockhead

Branded Mobil oil, sold at Halfords and used with success in the main engine and genset. Do you think fake oil gets onto Halford shelves? eek.

OK, so this is now two different voices saying that oil problems (overfilling; overused) can cause the cluthes not to grip. Good, very good. Since the problem corresponds to my changing the oil and overfilling it, this gives hope. I will first try lowering the level, then changing it again.

Thanks!!!


And thanks to Cal40John for the link to the manual. I have a few electronic versions of this manual, but this is the first with real text in the PDF rather than an image file which can't be searched.

According to this version of the manual:

KM4A, KMH4AAPI Classification .............. CC or higher
SAE Viscosity.................... #20 or #30(not available multi grade)

I think by "not available multi grade" they mean that if 20W or 30W is not available, you can use multi-grade. This is also encouraging.

it could quite well be reprocessed oil !
i would change it and use something like shell,more expensive but atleast you know what you are getting!

[Dockhead]

Originally Posted by sigmasailor

What is the type of transmission you have?
Some types of Yanmar are known to slip after a mere 500 hours; just Google 'yanmar sd 50 slip'.

It's a Kanzaki KM4A. Used not just for pleasure boats, but also for commercial fishing boats, so I hope a bit more robust than that.

[weavis]

Originally Posted by Dockhead

It's a Kanzaki KM4A. Used not just for pleasure boats, but also for commercial fishing boats, so I hope a bit more robust than that.

If you have a trawling selector.. it MUST be in H (high) when you are running.

[Dockhead]

Originally Posted by weavis

If you have a trawling selector.. it MUST be in H (high) when you are running.

There is a long section in the manual on the Trawling Selector. But it's optional and I don't have it.

Interesting that you are not supposed to exceed 1000RPM when in LOW. Some people think our engines will be destroyed if we run them that slowly.

[weavis]

Originally Posted by Dockhead

There is a long section in the manual on the Trawling Selector. But it's optional and I don't have it.

Interesting that you are not supposed to exceed 1000RPM when in LOW. Some people think our engines will be destroyed if we run them that slowly.

Ive had similar gearboxes and suffered when oil too low and overfilled. Not quite the same issues as as you but close enough. Personally, I would drop the oil to below the full mark, and take it for a spin....... then as atoll suggests, if it works, drop the oil altogether, change filter and start again.
I believe 15W-40 will be fine... thats what I used.

[MARINE ENGINNER]

Originally Posted by Dockhead

There is a long section in the manual on the Trawling Selector. But it's optional and I don't have it.

Interesting that you are not supposed to exceed 1000RPM when in LOW. Some people think our engines will be destroyed if we run them that slowly.

kanzaki km4a is not hydraulic driven it is mechanical clutch with a drive cone doesn't use 15w-40 it uses sae 20 or sae 30 monotype gear oil same oil that uses some tractor engines.
the problem you describe is a worn drive cone that engages some times to fwd and at reverse it goes better

p.m me your email to send all kanzaki trans service manual and some photos of a similar type km35p to see how is inside


M.E

[Dockhead]

So I dropped the oil level, and the gearbox seems to be working ok. Thanks to all who weighed in.

I can't quite tell for sure -- maybe it's still slipping a little sometimes, or maybe I'm being paranoid. I think I will try to find a laser tachometer to check it.

Now that my engine is running right again, I tried running the engine right up to redline and observing the speed. I could only just get 9 knots despite having a tailwind. Maybe the bottom is a little dirty or maybe it's slipping a little -- I can't really tell.

But if it were slipping continuously, surely the oil would be stinky? I don't have that -- oil is clear and smells fine.

[sigmasailor]

Good to hear it was a simple fix!. You are probably observing too good now and are seeing things which you normally would not see.

Still find it hard to understand why high oil levels in a gear box will cause slipping. I would understand it running hot.

If it doesn't become too warm I wouldn't worry about slipping too much. The oil would burn and you could see, feel and smell it.

[weavis]

Originally Posted by Dockhead

So I dropped the oil level, and the gearbox seems to be working ok. Thanks to all who weighed in.

I can't quite tell for sure -- maybe it's still slipping a little sometimes, or maybe I'm being paranoid. I think I will try to find a laser tachometer to check it.

Now that my engine is running right again, I tried running the engine right up to redline and observing the speed. I could only just get 9 knots despite having a tailwind. Maybe the bottom is a little dirty or maybe it's slipping a little -- I can't really tell.

But if it were slipping continuously, surely the oil would be stinky? I don't have that -- oil is clear and smells fine.

Maybe, even though I ran my gearbox with this oil, the recommendation by Marine Engineer, (whos knowledge I defer to), to change the oil for a 20 or 30 will solve the issue permanently.

Glad our experience with these things was of help. So often its more than the simple things.

[MARINE ENGINNER]

Originally Posted by weavis

Maybe, even though I ran my gearbox with this oil, the recommendation by Marine Engineer, (whos knowledge I defer to), to change the oil for a 20 or 30 will solve the issue permanently.

Glad our experience with these things was of help. So often its more than the simple things.

dear weavis i asnwer you about my knowledge with not an offensive way.
first of all you told to dockhead to change it to 15w40. so you are wrong of the type of oil you used in your transmissions, these transmissions AS PER MANUAL and without any service letter from yanmar they use sae 20 0r 30.
by changing now the oil the damage is still there you don;t do anything.


a teacher in the school was telling us every day RTFM .
READ THE F....... MANUAl :-)
So i don't tell you to trust 100% the manual because always you will find a minor percentage of faults but read it and then you decide how to proceed.
last year i overhauled 2 of these transmissions one km35p and one km4a. one owner was using ATF and the other was mixing sae 20 with 30.


just explaining what is going on with the trannys again with no offensive mood

[weavis]

Originally Posted by MARINE ENGINNER

dear weavis i asnwer you about my knowledge with not an offensive way.
first of all you told to dockhead to change it to 15w40. so you are wrong of the type of oil you used in your transmissions, these transmissions AS PER MANUAL and without any service letter from yanmar they use sae 20 0r 30.
by changing now the oil the damage is still there you don;t do anything.


a teacher in the school was telling us every day RTFM .
READ THE F....... MANUAl :-)
So i don't tell you to trust 100% the manual because always you will find a minor percentage of faults but read it and then you decide how to proceed.
last year i overhauled 2 of these transmissions one km35p and one km4a. one owner was using ATF and the other was mixing sae 20 with 30.


just explaining what is going on with the trannys again with no offensive mood

Um.. Im NOT a marine engineer. I accepted your knowledge was better. I defered to your experience.
Im not offended and glad for the advice. I merely stated that my choice of oil worked for me but as you pointed out,was not correct.
The written word makes it harder to understand the context.
My experience with gearboxes is that under or over filled causes issues.
Im glad he sorted it. IT might not be the whole answer and indeed it might need attention to the cone but for now he is moving a little better.

[MARINE ENGINNER]

Originally Posted by weavis

Um.. Im NOT a marine engineer. I accepted your knowledge was better. I defered to your experience.
Im not offended and glad for the advice. I merely stated that my choice of oil worked for me but was not correct.
The written word makes it harder to understand the context.
My experience with gearboxes is that under or over filled causes issues.
Im glad he sorted it. IT moght not be the whole answer and indeed it need attention to the cone but for now he is moving a little better.

yes the written word is a little bit strange as is my english and google trasnlator.
sorry for my misunderstanding my mistake.

[sigmasailor]

Not simply RTFM but: 'If everything else fails' RTFM........ ;-)