Starting a Diesel in Cold Weather

[rognvald]

There is a direct relationship to starting a diesel easily in warm vs. cold weather. Are there any practical techniques for starting a diesel when the weather is in the 30's and 40's or below? My engine is a Yanmar 3GM30F and does not have a pre-heating system?

[Adelie]

If you have compression release levers you might pop one or two open which means the engine starts rough but starts then add cylinders back to get it going smooth.

[TacomaSailor]

I've seen no need for special cool weather starting techniques for my Yanmar - 19 years and almost 3000 hours.

In 32 F degree air temp and 48 degree water temp:

I turn the key on my Yanmar 4JH2E and it starts - there seems to be no difference in starting performance between 32 and 82 degree ambient temp.

I've started the engine when the ambient air was about 25 and it cranked for less than 2 seconds before starting.

If the engine has not run for more than a couple days - I pull the fuel lever and crank the engine for 8 seconds, wait 5 seconds, crank for another 8 seconds to pump fresh oil thru the system. I then push the fuel lever in and turn the starter key and it fires within part of a second.

[S/V Antares]

Yes, warmer = easier. engauge the decompression levers to get the engine spun up then disengauge one, two then the last as each cylinder starts to fire. The faster the engine turns the faster it starts. Diesels and batteries do not like the cold.

If you are on the dock a small heater or heat lamp will make a big difference.

[Vasco]

My 3gm30f starts in cold weather. Might need a couple of cranks but it starts at freezing temperatures.

[Astrid]

Main source of wear on a diesel is cold weather starting as cold oil does not circulate as well. Up this way, Kim Hotstart applications for heating the engine oil in the oil pan are popular and definitely help starting.

Kim Hotstart Engine Preheaters

[RTB]

I have a 3 GMD (20 HP). The manual says to start at 7/8 throttle. I used to have hell starting on cold days before I found this in the manual. I think it retards the timing (or something like that?)

Ralph
Stewbilee | sailing away with R & B

[Sailmonkey]

Originally Posted by RTB

I have a 3 GMD (20 HP). The manual says to start at 7/8 throttle. I used to have hell starting on cold days before I found this in the manual. I think it retards the timing (or something like that?) Ralph Stewbilee | sailing away with R & B

Actually all it does is keep extra fuel on the engine without the governor cutting back until the engine is warmed up.

[Dockhead]

Originally Posted by TacomaSailor

I've seen no need for special cool weather starting techniques for my Yanmar - 19 years and almost 3000 hours.

In 32 F degree air temp and 48 degree water temp:

I turn the key on my Yanmar 4JH2E and it starts - there seems to be no difference in starting performance between 32 and 82 degree ambient temp.

I've started the engine when the ambient air was about 25 and it cranked for less than 2 seconds before starting.

If the engine has not run for more than a couple days - I pull the fuel lever and crank the engine for 8 seconds, wait 5 seconds, crank for another 8 seconds to pump fresh oil thru the system. I then push the fuel lever in and turn the starter key and it fires within part of a second.

Same with my 4JH3HTE. I do have a preheater, but I've never once used it. Starts instantly down to well below freezing (I sail all winter at latitude above 50N). As far as I can tell, if you've got decent compression and a strong enough starter motor, a diesel will start without fail, not like a petrol engine which can be finicky about mixture, get flooded, etc.

[Sailmonkey]

I have started both a yanmar and a Kubota powered light tower @ -40 deg F. Both started right up, but sounded like crap until the jacket water temp rose to roughly 50 deg F. No special starting procedures needed, but it's hard on the engines to do so as the oil I rather viscous!!!

[DeepFrz]

If you have a slip and outside power then it is well worth adding either a coolant heater or an oil heater or both. Your engine will thank you for it. In a recent thread someone recommended that the OP use a heat gun to blow hot air in the air intake and it seemed to work very well.

[westwinds]

Make sure the batteries and cables are in good condition for quick starting. While cranking the engine, use a volt meter or multimeter. Should not have more than 0.1 volts across each terminal and battery post. Also be sure to check ground side of battery for voltage drop. You can also use a hydrometer to check state of charge and condition for each battery cell, or look for resting voltage (no power draw for four hours). The percent of charge is 100% at 12.7 volts, 50% at 12.1, and 10% = 11.5

[sartorst]

Muti viscosity oils are important in these conditions, good cranking speed, 3/4 throttle,cetane boosters,heat and all else fails WD40,easyer on the engine than starting fluid ,engines tend to get addicted to ether based starting fluids
And in a case where I had no access to a heat source (heat gun)I heated a heavy metal rod (large punch)on the propane stove held with pliers then held it in the intake as WD40 was sprayed on it as it was cranked .the vaporized WD40 makes for exccelant combustion, start out with small squirts and build up so as not to cause a run away engine

[westwinds]

I have a block heater on a diesel here in Wisconsin. This diesel has electronic controls that retard the injection point to where the compression is at its highest when starting and it will start at -20 degrees without pre-heating. A block heater sure takes care of the problem if it is colder than that, but then I use a block heater if it gets much below freezing as an engine that is warmed up has a lot less wear. An electric heater in the engine compartment left overnight would also heat things up and make for easy starting. So, get a block heater. Also #1 diesel makes for easier starting when it is really cold. It's a little more expensive, but sure helps on staring.

Another thing to consider is the compression on a hard starting diesel. If the valves leak or the piston rings are not sealing correctly there may not be enough heat generated by compressing the air to ignite the diesel. You need all of that air compressed to get high enough temperature to start.

[jtsailjt]

Lots of good advice here. But unless you have already had problems, I doubt if you really need to take any special measures. Since boats are always immersed in a huge "heat sink" that's above 32F, even on the coldest days it's unlikely that the engine will get much colder than that.

I once had a diesel car engine that I would leave unattended for weeks at a time in northern New England and it would start reliably ( I had the biggest battery that would fit.) until temps got down into the zero fahrenheit range and even then it would usually start if I had remembered to add some anti-gel additive to the fuel when I filled it up. That said, if you want to be extra nice to your diesel and it's usually kept at a dock where electricity is available, either a coolant or oil heater would be a nice thing to do for it.