Yamaha 3JH3E and Kanzaki KM3A1 Marine Drive – Clutch Slipping
For a while we have been puzzled.
We would start the port engine and put it into gear. And all would be well.
Then we would stop for whatever reason.
And then we would put it into gear again – and nothing happened. It seemed like the prop wasn’t turning. Indeed occasionally that was the case. But in most cases the prop shaft was still going around.
Yet we were doing just 1.5 kts instead of 3.5 kts, using just the one port engine. And the same would happen in reverse – just no power when we try to maneuver.
Finally we figured out that the clutch must be slipping.
The workshop manual had a whole list of possible causes, but most seemed to do with oil pressure. I guess that the clutch needs oil that is not too thin, and not too thick, in order to work correctly. The gearbox case does specify SAE 30 oil, but a lot of people seem to think that Automatic Transmission Fluid would do the job better. That is most specifically NOT the case. Well, we didn’t have ATF in it, but we did wonder if perhaps the mechanic in Antigua had put the wrong grade in, and that now, when the oil heats up, it would get too thin and no longer work.
The mechanic who took a quick look at it started muttering about replacing the cones for about $1000. Hmm, not keen on that idea.
In any case we were well overdue for a transmission oil change (oops – mea culpa), so I bought the correct grade of oil, changed the oil twice, in order to totally rinse out the old oil, and then filled it up with ‘Genuine Yanmar Transmission Oil – SAE 30’ just to be absolutely sure we had the right stuff.
That was four days ago.
Well, since then we have not had any problems with it slipping. And today we gave it a very good workout which would previously have caused us problems.
So, it looks like it was all fixed with some fresh oil!
Phew.
Yamaha 3JH3E and Kanzaki KM3A1 Marine Drive – Clutch Slipping
Hi there,
We just had a similar transmission slip issue (today!). Did the “Yanmar brand 30 wt” oil change still solve this problem long term?
We have a 2002 Leopard 42.
Hi Fred,
So far, so good. We have not had any more problems with slip since we changed the oil. Since it is such a small quantity of oil, and since it is so easy to do, I plan to change it each time I change the engine oil.
The key is to find a low profile container that will slide under the transmission to catch the oil. I find that typically whenever I do something on the engine like changing the oil, the actual job takes about 15 minutes, and then cleaning up all the oil spills I made takes me another hour!
Good Luck with it!
Noel