YM2210 Vent Tube?

[Smoody]

Ok, I am not sure what this tube is called, I have some oil/wet stuff that sometimes comes out this tube, but not always, seems to do it when I have to turn it over more then a few times to crank it. Its minimal but I think this is called blow by? How much is to much and is it normal to occasionally get this?

I also have a YM2001 but the tube is extended down far enough to where as if it has it it spits it on the ground, so I can't compare.

Second, is it normally harder to start a 2 cylinder vs. a 3 cylinder yanmar? my YM2001 cranks right up first turn no matter temp, the YM2210 takes a few turns on a cold morning, and puffs out white smoke while its trying to start, after it starts the smok clears and I can shut down and crank back with 1 turn.

All this normal?

SEE pic for the tube im referring to, this is a picture I got off the internet so its not my actual tractor. The "red circle" is to show where the nasty stuff blows out onto the tractor frame.

Thanks

 

[deepNdirt]

it is a crankcase vent to prevent Crankcase pressure buildup, just as your pistons build compression in the cylinders they also can build up pressure on the down stroke in the crankcase, usually you wouldn't notice any oil coming from the vent tube, it is design to relief vapor pressure do to windage of the internal engine components and the pressure of return stroke from the pistons, when the engine is cold your oil level builds higher in the oil pan and the rotation of the crank will pickup the oil and disperting it creating windage/ pressure, as the engine warms the oil thins and can move thru the engine more freely, usually when you start seeing oil around the vent tube would be a good time to change the oil, if the oil gets too thick it will not move thru the engine freely causing the oil returns to clog and then build excessive crankcase pressure,

 

[Smoody]

Thanks DeepNDirt, that's explains it better. however I did just change the oil last week (Rotella 15w-40), however I am not sure if it done it before or after the oil change, I didnt notice it until yesterday. I cleaned the soot off the frame and I guess I'll know soon enough.

 

[California]

The vent tube is operating normally, ignore it. Cars used to vent to the ground like that. Then smog rules required retrofitting PCV's (Positive Crankcase Vent plumbing) which route that smog back into the intake so you don't see it.

As the pistons go down the air in the crankcase gets compressed, and that tube lets the crankcase 'breathe' to outside. Of course a worn engine will have more pressure in the crankcase, and coming out that tube, due to compression that got past the rings.

2 cyl vs 3 cyl starting. I was amazed that the 3 cyl YM186D I bought recently starts instantly. Even faster than any gas engine. My 2 cylinder YM240 used to fire on the first compression stroke but take a couple of revolutions to smooth out. Now running B90 biodiesel it doesn't start as readily and can take 5-10 seconds of smoky cranking before it fires off. I topped up the YM186D with B100, about B50 blend in it now, and it still starts instantly. I suppose improved starting was one of the reasons for upgrades beyond 1970's technology. I still prefer the 2 cylinder engine's torque however!

 

[normde2001]

Ideally your crankcase should have a vacuum, as measured by a "manometer". If there is pressure instead, could be a bad vent, (PCV), should only let air out, not in, bad head gasket, rings, plugged exhaust, or even bad dipstick seal. Bad HG or plugged exhaust could be a reason for your hard starting.

 

[tallyho8]

As the pistons go down the air in the crankcase gets compressed, and that tube lets the crankcase 'breathe' to outside.

I was under the belief that as one piston went down the other one came up so they did not compress the air in the crankcase but maintained steady pressure.

 

[California]

Approximately, but you still need some venting.

Off-topic trivia: I first started reflecting on this when I learned my BSA (ancient British motorcycle) had side by side cylinders that went up and down in tandem, like an oversize single. This made it even-firing, one impulse per 360 degrees of crankshaft rotation. The downside was a huge volume of air, smoke, and oil droplets forced out the crankcase vent with each stroke. This was directed at the chain and described as a 'feature' essential for lubing the chain.

Then Honda entered the American market with 250 and 305 twins. 'Scrambler' (high pipes, no low end torque) and 'Dream' (touring trim) if I remember correctly. Both idled real fast with a curious loping rhythm. This was a combination of a light flywheel and pistons that rose alternately, giving a firing pattern of one cylinder firing 180 degrees after the other, then nothing for another 540 degrees of rotation. At the time the traditional motorcyclists dismissed this design as crackpot like an electric motorcycle or something. Actually Honda soon buried the British in the light-bike market. Honda's biggest advantage? Their motorcycles didn't make a puddle of oil where they were parked! As you noted, the near constant crankcase volume meant little to no oil pushed out the breather.

These Yanmar twins are like Hondas - The cylinders rise alternately and they fire 120/540.

 

[Kernopelli]

Approximately, but you still need some venting.

Off-topic trivia: I first started reflecting on this when I learned my BSA (ancient British motorcycle) had side by side cylinders that went up and down in tandem, like an oversize single. This made it even-firing, one impulse per 360 degrees of crankshaft rotation. The downside was a huge volume of air, smoke, and oil droplets forced out the crankcase vent with each stroke. This was directed at the chain and described as a 'feature' essential for lubing the chain.

If I remember correctly, Harley used to use it as a chain oiler as well. The difference in the Wisconsin 2 cyl.THD and TJD engines was their firing order, the THD's fired together and the newer version TJD used a 180* crank. Hard to imagine how they figured a twin would run better without opposing each other to some degree.

 

[careyo63]

After getting use to an old 2cyl. 650 Spec.Yamaha years ago made my Yanmar 2TR20A pretty sweet and bring back some memories thank goodness without all the vibration

 

[Smoody]

So to be clear is some wet stuff coming out of the crankcase tube normal or should it not do it at all?