Analyse this (yanmar)

[ColinR]

My 20 year old 2gm 20 is very slow to start from cold. It turns over but doesn't fire. I leave it a bit, try again, often end up turning off the water inlet so I dont flood it. Eventually it fires. Once its been run it springs to life at the touch of the button for the rest of the day. The batteries are new and usually fully charged with smart charger and wind gen. It uses no oil,doesn't smoke except when cranking it to start it in the first place, the injectors were just serviced and it never misses a beat when running. the compression was tested recently and found to be about 230, down from an ideal of 300. I assume the low compression is the reason for poor starting, but the fact is uses no oil suggests that this is more down to the valves than the piston rings. At least this is what I hope as reconditioning the head is viable, if it needs the pistons doing as well it is probably not worth it. what you think? I'm not that knowledgable about engines, this is gleaned from talking to the Yanmar engineer and a bit of common sense and I would welcome a second opinion.

Many thanks

colin

 

[oldaljones]

Hi Colin I had a similar problem with a volvo 2003 about 15 years ago it turned out to be the valve seats which were pitted in the end it would only start with Easystart (evil stuff but will get you going in an emergency) Volvo dealers quoted about £440 I removed the head and took it to my local automotive engineers who fitted new hardened valve seats (6no.) for £80.00 + new head gasket about £100 total. It was then like a new engine I hope yours is as easily remedied. Best of luck.

Old Al

 

[lw395]

Not sure why it starts easier for rest of day. Does the starter spin it faster? Mine started a lot better after the charging system was upgraded. However, compression does sound low, I would tend to agree with oldaljones, sounds like a good engine needing a little attention to the valves.

 

[aluijten]

I've had exactly the same thing with a Volvo 2003. In this case it turned out to be a tiny leakage on the primary side of the fuel system (I mean the point between the low pressure pump and the high pressure pump(s).
What happened overnight is that the engine cooled down allowing air into the system. As the fuel tank is positioned in the keel, gravity pulled all the fuel from the system, making the cold-start very painful. The rest of the day the engine would start perfectly.
Because of the same reason I also had a tiny fuel leakage during run-time that was hardly noticeable.
The cause of all this turned out to be a forgotten washer in on of the fuel hose connectors (forgotten by someone else).
Hope this helps,

Arno

 

[ColinR]

Thats interesting. How did you find the leak?

Colin

 

[notyet]

We have the same engine, about the same age, with similar symptoms and find that we need full throttle to get it started when cold. After that it starts perfectly.

I don't know if this is a problem, I just put it down to the vaguaries of an ageing engine.

 

[aluijten]

Actually I did not. More precise, I was so annoyed by the whole thing that I decided to replace all the hoses and washers on the primary side.

Mind you, a Volvo Penta 2003 has a bit of a funny set-up with 3 more or less independent high pressure pumps sitting next to each other all driven by the camshaft. The supply of fuel and the return lines to and from the pumps are all done with interconnecting bits and tubes, partially with rubber hoses of approx. 5 cm long. This all sits on the other side of the engine as where the injectors are

Due to the nature of the problem I had the feeling air was entering the system. Also after careful inspection I found some proof of the tiny fuel leakage but I was not able to pinpoint the origin other then a rough area (being the fuel pump side).

So what I did is looked at the drawing of the engine, noted down all part numbers of the washers and rubber hoses and ordered the lot.
Then during the take-apart I found out one of the washers was actually missing.
So I replaced all the parts I noted down and have never had an issue with poor starting any more.

Cheers,
Arno

 

[misterg]

Spooky!

I asked a pretty much identical question (also 2GM20) within the last fortnight. The answers I got indicated that I wasn't using as much throttle on starting as most others.

See previous thread

Andy

 

[ColinR]

well that is interesting. Thanks for the link to the previous thread and thanks to everyone who has responded. I use about half throttle, I'll try increasing it. Its much harder to start from cold than in previous years, I have never thought of it as a problem before but now its raising questions over the state of the engine. I plan to have the head taken off in the winter and hopefully get a better idea of whats going on. I do suspect the low compression and hope thats down to valves.

Colin

 

[toad]

In addition to what others have said I would also check the exhaust injection bend for blockage due to carbon build up, a ten minute job. Or if when you take the head off the piston to head clearance with a piece of soft solder and a micrometer. All Marine engines are liable to water getting into the cylinders and very slightly bending the con rod and lowering the compression ratio.