Advice please for Yanmar Newb

blunted

Super Anarchist
1,508
359
Toronto
In my experience, this is incorrect.  Turning off the key kills the field, which kills the output of the alternator, leaving it in a "safe" condition.  Disconnecting a running alternator from the load (battery) is what kills the diodes, as the power then has nowhere to go and the voltage rises too high for the diodes. 
What ropetrick said is precisely what is in the manual. Shut down the engine, then turn off the key.

 

SloopJonB

Super Anarchist
68,646
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Great Wet North
You'll get a feel for what speed position to set once you've started the engine a few times. My 2GM will start at idle speed in the summer or when it's already warm but needs full speed when it's -5C. I don't have glow plugs and I also need to set a fast idle after it's started (1200-1500 RPM) until it gets some heat into it when it's cold out.
This.

When my 2GMF is hot it only takes a bump of the switch at idle to start - just the same as my digital injected cars.

Cold it takes full throttle and 4 or 5 seconds of cranking to light.

 

Zonker

Super Anarchist
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Canada
If BRAND NEW - and if it has a mechanical kill cable: pull the cable. Crank for several seconds. Stop cranking. Push in cable. Then start. This gets some oil to bearings without any combustion loads. 

 

Left Shift

Super Anarchist
10,532
3,271
Seattle
My 4 cyl Yanmar prefers that I apply throttle when starting. Cold out?, give her, hot out?, half way throttle. As soon as it fires I back it down to idle and give it a minute to compose itself.

Yanmars want to come up to proper operating temperature for optimal performance so it's not the end of the world to give it a little extra before you put her into gear. It may take 15 minutes of running kind of hard to actually get to that OPTIMAL temperature. You can run it as less than optimal and that's ok, it's just not optimal.

Once you get her going, put some load on it and let her rip. All diesels prefer to work hard. So feed her what she wants. you need to get over 1500 rpm to kick in the alternator and before you shut it down it's a good idea to rev her up to 3000 to blow the carbon out before you shut it down.

Yanmars are awesome, but don't baby it, put the spurs to her.
Haven't seen this in the above, but my mechanic says to run the engine up to full throttle under load and then calculate 80% of those max RPMs and that's your target running speed. 

Starting cold, we always give it 3/4 throttle and then promptly back off to a fast idle until smooth.  Then walk to the back of the boat and wait for the water to spurt out the tail pipe - every time.  Once warm, it will start at idle pretty much all day.  But check the exhaust, again.

The main thing is to check both your engine and saildrive lubricants and zincs regularly, and make sure to replace the sail drive and the prop zincs sooner than later.  

And go to school on the meaning of engine smoke and lubricant colors.  If you have saildrive lubricant that looks like chocolate milkshake, you are officially having a bad day.

 

SloopJonB

Super Anarchist
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Great Wet North
Haven't seen this in the above, but my mechanic says to run the engine up to full throttle under load and then calculate 80% of those max RPMs and that's your target running speed.
Or you could look in the manual and use what Yanmar recommends.

Your mechanics method does not factor in an incorrect prop or any of the other problems that can limit RPM - you'll just run at 80% of an incorrect RPM.

 

Left Shift

Super Anarchist
10,532
3,271
Seattle
Or you could look in the manual and use what Yanmar recommends.

Your mechanics method does not factor in an incorrect prop or any of the other problems that can limit RPM - you'll just run at 80% of an incorrect RPM.
Well, yeah.  You do have to have the right prop.  I have had mechanics put feathering props together to the wrong setting and the engine couldn't get much above idle under load.  Weird sensation.  

Oddly enough, my mechanic's method and the Yanmar recommendation come within 50 rpm of each other.  For most situations, the 80% "rule" seems to work as a reasonable way to find a steady working load.  At least it seems to have worked over half a dozen different boats.  I must have the right prop on on all of those boats.

 

Snowden

Super Anarchist
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UK
What ropetrick said is precisely what is in the manual. Shut down the engine, then turn off the key.
The reason the manual says that is that the warning lights on the engine panel (oil, temp, saildrive seal) don't operate if the key is turned off. The alternator load does not touch the wiring to the panel for obvious reasons, the idea that you bugger the alternator by switching the key off while the engine is running is a myth. If you don't believe me look at the wiring diagram:

wiring_eng_yanmar_original.jpg


 

longy

Overlord of Anarchy
6,757
1,126
San Diego
Yes, follow the wiring: on all stock Yanmar wiring looms, alt output goes direct to starter solenoid, where it is stacked along with the power power supply to to the ignition key and the power supply from the battery. So alt is always connected to batt. 

However, if you turn key off with engine running, a push button kill will not work, as it will have no power to send to solenoind.

 
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As as was noted earlier - if the engine is brand new, then that is a different deal.

Meanwhile if its a used engine from a boat you recently purchased...

#1. Go download the manual for the engine (and look at the serial plate on the motor itself, and while at it, the transmission) and don't rely on the broker or surveyor to tell you what you have.  Follow the manufactuer's instructions, and if needed - yes, a little extra open throttle then waiting for the starter to cool down also works.  If it does not start within ~10 serious tries with a bit of time in between then possibly something else is going on - like fuel vacuum in the fuel line if the tank is below the motor (which is commonly the case for a variety of reasons).

The above said, if the motor is not 'brand new' - after you have her purring and put a few hours on, be sure to:

#1. Change the oil & filters, maybe twice, and if the Yanmar has a secondary oil filter (little bit more of a chore) change that one with the last oil change.

#2. Change the coolant and be mindful about what coolant you use.

As others have asked - it is 'brand new' and if not any idea how many hours on it so far?

 

sailorman44

Member
281
71
CT/FL
Here is some information which hasn't been mentioned yet. I have a 3GM30fcv. It has a compression release lever for each calendar. Don't  know if the 2YM15 has this feature. When the battery is too low to start the engine, releasing 2 of the levers reduces the load on the battery and the engine will start on one cylinder. when it is running on one cylinder flip the compression release lever and the other cylinder will join in.  Releasing the compression is also useful at the beginning of the season before starting the engine for the first time to spin up the engine and get oil to all the bearing with out load.

 
Alternatively, if you  you have a house and a cranking battery put your battery switch in the "both" position which puts the house battery in parallel with the cranking battery to get extra cranking power. Don't forget to take the switch out of "both" position or the batteries will equalize and you will have two low battery. Also do not move the switch through "none" when the motor is running as this will blow the diodes in the alternator.


 
If you have a MaxProp feathering prop on your sail drive, after you have the sails up and are ready to turn off the engine, with the boat moving a at 3 knots or better, turn off the engine put the sail drive in neutral, wait 3 boat lengths for the prop to feather and shift into reverse to lock the shaft.

 

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