Yanmar 1GM10 cold starting

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Markysailingsparky

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I'm not an engine boffin and I'm just interested to know why the engine, on a cold day, takes so long to start? The engine is a reconditioned one put in this summer and its always been a quick starter, since the cold weather has hit it is normally starting on the third attempt-following the guidance of only running starter motor for 15secs max! Once warm it will kick in immediately-is it just Diesel engines or is it something more??? Please don't hit me with scientific jargon-simple replies please....
 
So your saying Nick-it's just like an old person.....takes a bit of kicking in the cold but will get there! I have been starting half throttle.....would you advise no throttle or full?
 
Quite simply the cold turns your engine oil to treacle. Imagine walking through 12" of snow against walking on hard turf. That is basically what your engine is up against.
 
You may find it helps to turn the engine over on the starter with the decompression lifted. Gets the oil moving and a bit of heat in. Full throttle might also help.
 
Cheers! I just thought I was being stupid or was something more underlying! I came across a comment about starting with seacock being open and backing into exhaust? I don't know how I could get it started then run into cabin, remove stairs and turn sea cock before warning signal would tone! Is this just a random gremlin or a common problem?
 
The pump lifts very little at cranking speeds so little danger with a few extra seconds to get it going.
 
Following that comment Tranona-how much water should be coming out on idle/full? I'm used to outboards where you have a continuous flow to watch whereas on this yanmar it's like watching someone being sick....gulps and dribbles but water always coming out!
 
It's not just the oil that's cold, this time of year. So is the engine and the air being sucked into the cylinders. Compressing the air heats it up (Charles Law:- PV/T is a constant) and on a spring or summer's day, a couple of strokes is all that's needed to heat the air in the cylinder enough to fire the dieso. This weather it takes a lot longer, simply because the heat generated by each stroke is leached out by the cold mass of the engine and any residual heat in the charge is pushed out the exhaust. The 1GM10 doesn't have a glowplug.

Turning it over on the decompressor is easier on the battery and starter motor. Once the engine is up to cranking speed, drop the decompressor and the engine should fire up after three or four revolutions, although they can take up to 20. I start mine on 1/2 throttle during "warm" weather and about 3/4 when it's cold. Keep the starter on until the engine fires at least twice consecutively.

If the starter motor starts to slow down, you're draining the battery. Stop and leave it for about five minutes to regain it's composure. It always helps to have a fully charged battery. Batteries don't work as well when they're cold either.

Depending on your installation, water should be pushed from the exhaust every three to five power strokes, it's got a long way to come from the water trap.
 
Water flow - it comes out in small gulps (good word for it) cos the exhaust pressure has to build up in the water trap before it can shove a cupful out. Don't expect a lot of water from a 1GM.
Giving it a short burst with decompressor on should stir the oil up (as suggested). But not too long apparently - mechanic pointed out that diesel is still being injected and might build up with risk of backwards starting.
I've got the option of using a 12v caravan hair dryer. Croc clips to the house battery and point it up the air intake.
I've got a riser missing from the bottom of the steps so I can reach in for water cock. Maybe you could remove the steps to give access until engine started
 
The symptoms you describe are exactly the same as for my 1GM. As far as I am aware, it is in good order. It always starts in the cold - eventually!
 
As usual great advice! It is comforting and good to know that my worries are little more than that...I'm planning on getting a service shortly as being a reconditioned engine, fitted this summer, I just want oil etc changed as it has settled into the boat...looking for a nice day too to get into the North Sea and get a good sail out of the jeanneau...so far I have just been shifting all 27 foot at 6knots up and down the river to realise the pier is alive with white horses and an almighty swell!
 
I've got the option of using a 12v caravan hair dryer. Croc clips to the house battery and point it up the air intake.
I've got a riser missing from the bottom of the steps so I can reach in for water cock. Maybe you could remove the steps to give access until engine started[/QUOTE]

What a good idea. How much do they cost?
 
I'm sure it says in the manual for the 2gm20 that you should use full throttle on cold start as this retards the injection timing.
I think it will be the same for a 1GM
 
Haven't checked against the manual (I don't have a Yanmar), but I seem to recall that you should open to full throttle before attempting a cold start as the fuel slide then opens beyond the normal max until the engine fires, which pulls it back to normal. That is the Yanmar method for overfuelling to achieve cold starts. Having said that, most will start on something approaching full throttle after a few compression strokes have warmed them up a bit.

Rob.
 
Markysailingsparky said:
Following that comment Tranona-how much water should be coming out on idle/full? I'm used to outboards where you have a continuous flow to watch whereas on this yanmar it's like watching someone being sick....gulps and dribbles but water always coming out!
Click to expand...

I measured mine at around 1.5 to 2 litres/minute at tickover. It might vary a bit depending on the amount of plumbing (valves, filter, inlet pipe dia etc) and I only measured it roughly with a jug and a watch.
 
Markysailingsparky said:
....... I came across a comment about starting with seacock being open and backing into exhaust? I don't know how I could get it started then run into cabin, remove stairs and turn sea cock before warning signal would tone! Is this just a random gremlin or a common problem?
Click to expand...
Yes, there can be a problem apparently if the engine refuses to fire even with repeated cranking (this applies to water-cooled marine engines in general, not just Yanmar 1GMs) and in that case you will need to close the seacock before too much water gets pumped in (can take a short while as noted above). Once engine runs you will have plenty of time to open seacock again before anything gets too hot.
 
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