Yanmar 3ym30 oil drain plug

[philg71]

So I found the oil drain plug located on the left hand side of the engine below the dipstick. I found it much easier to drain the engine oil this way, rather then sucking it out the dipstick tube. However... All was going great until I loosened the drain plug too far and it came all the way out. Now I can't seem to get it to engage and screw back in. Like there's something on the inside of the casing that it screws into. I feel like a right dummy. Lol.What do do?

[Seymore]

Talk to your Yanmar dealer. Yanmar says to not drain oil using the drain plug because they've designed it so, when the drain plug is removed, it can't be reinserted by mortal people (?). They positively say to drain the oil through the dipstick hole.

[philg71]

Thought that might be the case. Thanks for replying. Will contact Yanmar and take on the 'what, you were so dumb that you pulled the drain plug out?'. Oh well, it did a really great job of draining the oil, including little bits of grit that I never got out before when sucking the old oil out of the dipper tube

[GordMay]

A dentist might be able to help.
They're used to doing dexterous finger work, upside down and backwards.

[a64pilot]

Since you want to drain from the bottom, you may want to get one of these, designed for aircraft so they are safe, but the idea is you slip on a hose and push the valve and that lets the oil flow, slip off the hose and pull the valve closed in one motion. After install, no tools needed.
https://www.aircraftspruce.com/catal...ickkey=3051788

Of course you will need to determine your thread size

[Bill O]

Seems aircraft parts are relatively expensive for an oil drain plug. While we do the dipstick drain now, do feel draining the oil out of the lowest part of the sump via the drain plug would be much better. Was very surprised that a "marine" Reverso pump was just a dipstick sucker and until you went up in models did it get you to the oil drain plug version.
Would like to see the aircraft version in person to see if it was visually sufficient to quickly tell if you accidentally left it open. IMO the handles on a seacock/ball valves are much easier to see at a glance if they are open/closed and would think something similar could be done for the oil drain valve. In addition a spot to wire it in the closed position would be a good safety feature.


Bill O.

[a64pilot]

Aircraft parts are expensive for what they are for a few reasons.
You really can’t mess this up, it’s an unmistakable twist lock and spring back to closed.
Aircraft safety wire everything, including the oil filter for example, yet this plug doesn’t require it, and where many or most plugs are on a boat, safety wiring would be difficult indeed.
I don’t even know if my 4JHE even has a plug, personally the dip stick is good for me.
But for those that want to drain out of the sump, these plugs make it simple.
Oil change interval on my little C-140 is 25 hours and to change its oil with this quick drain I don’t even need to pull the cowling, just reach up and slide a hose over the plug and push, and when finished a slight twist and pull the hose off.

[Bill O]

We are due for an oil change and this thread reminds me to look into creating my oil change system on my Perkins 4.236.

I'm feeling more thankful now that our oil changes are every 200 hrs and not 25 hrs.


Bill O.

[Disailor]

I was going to remove the oil pan & weld in a drain plug however I found that the dipstick tube on my 3ym30 ends at a banjo bolt at the very bottom of the sump. Ran the engine for 30 sec while on the hard & all the oil was sucked out of the tube in less that a minute!

[a64pilot]

Most all if not all marine dip stick tubes go all the way to the bottom of the pan of course so that you can suck the oil out, just using the tube.
Most automotive tubes do not, for this reason you can pull the stick first time on a car and read the oil level.

But because a Marine tube is below the oil level if the stick forms a tight seal at the top of the stick like it should then when the tube cools off the vacuum formed from the air cooling can pull oil up into the tube and give a way high reading, that’s why you have pull the stick, wipe it off and then try again on a boat.

[EmeraldCoastSailor]

I’ll restate a trick I use to get most if not all dirty oil out via dipstick sucking. Of course warm the engine up a bit and then start the sucking process. Just as you nearing the end and the gurgling starts add 1/4 quart of fresh oil (amount doesn’t matter) via oil fill. The fresh oil will of course be sucked out but with it will be the remnants not normally removed. My oil is honey colored for several months after every annual oil change so I believe it works.

FWIW, when I first bought my 3YM30 equipped boat I tried to remover plug for first oil change but it wouldn’t budge and I didn’t want to fight it so I bought dipstick removal unit. I never knew it was taboo to remove and I dodged a bullet on that day.

[MorwrMeic]

OK - dumb question coming up: "Seymore" states that Yanmar say we shouldn't use the drain plug coz we'll never be able to re-fit it ...so why is it there?!!! I moaned about these Yanmar engines overheating if you need to motor on full RPM on the Lagoon website as I loved my Beta engine on my old boat - you could go full RPM ... forever ... and it wouldn't let you down/overheat in a difficult situation when you really need your "Iron Horse"!!! Why are Yanmar's so popular? ... and yes, I have 2 3YMs on my Lagoon 420 and both overheated when I needed to go on WOT to avoid crazy shrimp trawlers descending on me in a major shipping channel? I limped back on low revs and checked everything and only conclusion was they had overheated ... poor little things!

[a64pilot]

Your engines should not overheat it run at full throttle, now many Yanmars are limited to one hour of operation at full throttle, but if properly propped there should be nothing you can do to overheat one.