Yanmar 1GM10 juddery gear engagement ... solved?

[JumbleDuck]

Sorry, I can't find the thread in which this was being discussed ...

In common with quite a few other people, I found that gear engagement on my 1GM10 was getting a bit juddery. Going from neutral to ahead gave a bangedy-bangedy-bangedy-whoosh effect, and it often took a good belt of full ahead to get proper engagement.

I assumed that my cones were getting glazed, and had decided to put up with it for now and pull the engine and box next winter to sort it out. Then I thought of checking the gearbox oil level which to my embarrassment I realised I had not looked at since getting the boat.

Checking it should have been easy once I worked out that the dipstick is attached to the filler screw, but was made hard by the complete absence of any obvious marks on the dipstick. However, the fact that only the very tip had oil on it was a bit of a dead giveaway.

So in went 0.3l of engine oil, as per manual, and as far as I can see the problem has been solved: both forward and reverse now engage with barely a hint of a judder. I'm a bit mystified about where the oil went - there is no trace of it in the tray under the gearbox - and I hope I haven't done any lasting damage through neglect, but I offer this tale in the hope that fellow judderers might find that the same solution works for them.

 

[Mel]

Can you tell us what level you have on the dip stick once you put in the exact amount of oil after draining down. Also was this taken after screwing the device right down first ?

 

[JumbleDuck]

Can you tell us what level you have on the dip stick once you put in the exact amount of oil after draining down. Also was this taken after screwing the device right down first ?

Sorry, not at the moment, as I didn't drain it - my vacuum oil sucky thing is at home. I'll do it properly when I can. According top the manual the level is checked with the plug unscrewed and simply resting in place and like that there was, before I topped up, just a hint of oil at the very tip.

 

[Tim D]

The line just above the bottom of the dipstick is the upper level, oil checked with the dipstick filler cap resting on the top of the thread flange and not screwed in, SAE 20 or 30 if you dont have a manual its available easily with a bit of research

 

[JumbleDuck]

The line just above the bottom of the dipstick is the upper level, oil checked with the dipstick filler cap resting on the top of the thread flange and not screwed in, SAE 20 or 30 if you dont have a manual its available easily with a bit of research

My manual says same oil as engine, so cheap 15W40 from Lidl is what it got. I didn't have net access when I was sorting the problem, and the printed manual is, as far as I can see, silent on what the marks are (the bottom one is apparently the bottom of the dipstick, so not really a mark at all) though it tells you to use them.

Thanks for the comments, folks ... I think my point, that it's worth checking gearbox oil levels if engagement is juddery, stands.

 

[Tim D]

Assuming its a km2p-1 Go to page 31 and 32 of the manual in the link below.

http://www.yanmarmarine.eu/theme/ya...manual/1GM10-OM/1GM10_OPERATION MANUAL_en.pdf

Yanmar technical

http://www.yanmarmarine.com/theme/y...nical-outline-drawings/pdf/outline KM2P-1.pdf

Some earlier manuals pics show the dipstick hovering over the filler port and arent very clear, take a look at a later almost identical manual and you will clearly see a diagram which explains very clearly.

If you over fill your gearbox too much you run the risk of popping a seal, 15w40 wont hurt in the very short term but I would suck that out and put in either 20 or 30 if you want it to last, if your not bothered and are happy to repair it then leave it as you have it