Problem starting Yanmar 1GM10

[Guest]

I have a new Yanmar 1GM10 fitted, After not being used for a month we used it last weekend. The engine was turned over to lubricate Friday and it started with no problem. Again on Saturday no problem. On Sunday we became becalmed when approaching our mooring creek. This time the engine wouldn't start. It was turned over for about 30 sec's twice and nothing. I used the cold start given in the manual (not handbook!) of max throttle and using decompression lever. This time after it started turning over it reluctantly started. Ewe ran if for about 30 minutes and after getting on the mooring turned it off and restarted just before leaving, started first time.

The batteries were OK, reading about 12.8v, indeed it was turning over well just not starting. It could hardly be called cold either, indeed it was colder on Saturday. I am concerned that something may not be right and would be grateful of any advice offered so I have some idea of what may be the problem, if there is one, before calling in the fitters.

 

[Guest]

I am not much of an engineer, but I have had my 1GM10 for 14 years. They are very reliable engines and provided they are given clean diesel and still have good compression they will start.
Suggest you check compression. This is a new engine so (from memory) it should be about 400. Mine will just turn over by hand. It it feels solid and will not turn at all, it may have "hydrauliced". Do you have an anti-siphon valve fitted in the cooling water systen? If not, fit one very soon.
I assume the fuel cock is fully open and there is plenty of clean fuel in the tank. Look at the water separator bowl( usually installed below the primary filter) - there should be no water seen in the glass. Does the diesel look clean? Try bleeding the system. If air bubbles out, you have an air leak, probably around the filter.
If engine starts after bleeding fuel system, leave it running, in gear, for at least fifteen minutes. If it will not run for this length of time, my money is on a leak in the fuel sytem, or a plugged filter- note there are two filters, primary and secondary. Check cooling water discharge while engine is running.
Take heart! Unless you are very unlucky these engines will run for years without problems.
You will probably receive a lot of responses from more eminent engineers, but the above guidelines and suggestions may help.

 

[brian_neale]

I have to say that my 7-year-old 1GM is also a good starter. From cold, I usually start it on the handle, for several reasons. It keeps me fit! It reduces wear and tear on the battery. If it starts OK on the handle, then it has to be in pretty good shape still. There is a knack to starting it like this, and the throttle setting can have a significant effect on ease of starting, although I have never seen anything in print about this. I do use the starter motor at times, but almost always with the help of the decompressor, which really lets the starter motor get the engine up to speed and gives the best possible chance of starting.

My experience of air in the fuel is that the engine will stop while running. I am not sure that there is much chance of air getting in while the engine is stopped. In any case, the engine is not self-bleeding, so this would not explain why the engine subsequently did run OK.

Do diesel engines suffer from "flooding" or similar, like petrol engines? I would have thought not, but can an expert answer this?

 

[vyv_cox]

In view of the age of the engine and subsequent starting it is highly unlikely to be anything mechanical that is at fault, e.g. compression. Temperature is not an issue.

My first thought is fuel starvation. In installations where the fuel tank is above the engine, a leak in a stationary engine will result in diesel coming out, rather than air going in. So assuming that you have not seen puddles of diesel on the engine, this is unlikely. (On a running engine air can be drawn into the suction pipework upstream of the lift pump)

One possible cause of your problem, that I have heard of on new engines, is that the needle in the injector nozzle is not seating properly. When the engine is stopped some fuel can leak out into the cylinder and it takes quite a few seconds of operation to bring fuel back to the injector. The problem may be due to a piece of swarf or some deposit, or perhaps some roughness in the machining, which seems to fix itself as running-in progresses. I suspect it is fairly common but is only really an evident problem on single cylinder engines.

It would not be surprising if it never happened again, so don't start expensive investigations just yet.

Incidentally, running engines for a short time, just to make sure they start or "to lubricate (??)" is the worst thing for them. The majority of wear takes place in an engine in the first minute of operation and shutting it down cold allows condensed sulphuric acid to corrode the bores, rings and pistons.

 

[Peter_the_Grate]

Ours is about 12 years old and was reluctant to start at times until we moved the battery during the last winter lay-up. The move required a new cable run and we used the biggest cables and terminators that we could get, 12 mm I think. Since then it starts straight away. The original cables and terminators looked OK but I guess they weren't. We've never done anything to the engine, apart from change the oil and filter at the end of each season.

 

[Mel]

I also own a very reliable 1GM10. The only time it failed me was just after doing a fuel filter change
when I failed to vent/bleed all the air from the fuel system.

I totally agree with the advice that vyv cox has given. Diesel engines work by compression of fuel injected.
A new engine is very unlikely to be suffering from a compression problem. The lack of fuel is the most likely
cause.

 

[johnt]

I had an almost identical problem with a Yanmar YSE8 a couple of years ago. it was caused by a careless shutdown which left unburnt fuel in the cylinder.

On attempting to restart it just didnt want to know, and we finished up ghosting at about 2 knots for several hours. Entering Vaberge in the dark is fun! (NOT)

The following morning I was all set to start taking the engine to pieces, but I gave it a spin over first........IT STARTED FIRST TIME!

so there you have it ..YES you can flood a diesel engine!
And it will probably never happen again.

Operator error strikes again!

 

[johnt]

PS by spinning over with the lifter on you cleared most of the unburnt fuel, hence the reluctant start, just like a car engine!

it didnt work with mine tho'

 

[Guest]

You've had good advise from everyone but with a new installation a fuel leak is the most likely. A leak does not allways show, as the engine pulls air but doesn't drip fuel when static. Check all you're fuel connections. Also do you have a CAV 296 fillter? They cause most air problems. Check all its gaskets.
A deisel can also flood for a knackered nozzle in the injector, but only on older engines.

 

[bob_tyler]

"The engine was turned over to lubricate Friday"

Don't do this unless you run it enough to get to working temperature before switching off.

 

[Guest]

What I did was as instructed in the handbook, when if unused for over a month you are told to turn the engine over by pulling the stop cable and use the decompression and turn it over for a short time to spread the oil. After that I started it, first time and with no problem and it was run for 5 minutes before it was used for a further 10 minutes. The following day again it started with no problem on two occasions and was only on the third day, after sailing it wouldn't start etc.