Yanmar 1GM10 has problems cold starting and revving!

[DangerousPirate]

So since yesterday I sit on my engine and try to get it to work.

The engine is going, I get plenty of white smoke at the exhaust and if I run the starting motor long enough I get the occassional fires, but it takes a long time to get there. At some point I got the engine warm enough(?) to start it within seconds, but then I had problems revving the engine up. I am not sure what causes that suddenly. Before the winter it was all fine and the engine started everytime right away, no issues ever. A notable issue was that I couldn't revv the engine up very much or I would get some error blarring at me (but don't know which thanks to the previous owners work with the controls). I suppose I could go maybe 2/3 before it became an issue. But I was going to address that after the winter.

Well, that aside. Cold starting problems. And once it's warm, it still won't rev up. I gradually increased it up to a certain point and if I go beyond that the engine just dies on me and I have to restart it. I hoped if I run it on full speed for a couple of minutes it'll blow out the build up and gets the engine back. But I ran out of time, I am back here again and now the engine won't start again.

Now not sure what to try before I get someone to service it (long overdue anyway, but expensive$$$)

 

[garymalmgren]

RE
I am back here again and now the engine won't start again.

Now not sure what to try before I get someone to service it (long overdue anyway, but expensive$$$)

It looks like you have a lose of compression and / or a coolant water leak.
The first thing to check is the head gasket and head.
You can do almost anything yourself on a 1 GM 10.
Download a manual, check youtube an away you go.

Gary

 

[DangerousPirate]

RE
I am back here again and now the engine won't start again.

Now not sure what to try before I get someone to service it (long overdue anyway, but expensive$$$)

It looks like you have a lose of compression and / or a coolant water leak.
The first thing to check is the head gasket and head.
You can do almost anything yourself on a 1 GM 10.
Download a manual, check youtube an away you go.

Gary

My engine is very inaccessible and cramped. So can't do to much about it myself. I can access everything fine in the front, but with everything in the back I kinda need to feel for things, which doesn't work if you have no experience with the engine.

I manage to change the oil, connect the electrics, change an impeller and simple stuff like that. But Idon't think i'll be able to take it apart und put it together. And lifting the engine out is not an option really.

 

[andsarkit]

The 1GM10 doesn't have heaters and so will always be more difficult to start in winter. Mine starts instantly in the summer but needs a bit of a churn in cold weather.
Check the compression if you can. Is it hard to turn over the compression stroke with the handle?
Check for blockages in the exhaust elbow and hose.
Check for fuel blockages or air leaks in the fuel line.
Try spinning it up with the decompression lever up for a few seconds so the momentum carries it over the first compression strokes.
The alarm when under load could be overheating. Does the top of the block feel very hot?

 

[Rappey]

A friend has cold starting problems. Once hot it's fine.
His fuel lift pump was weak. A new one mad it better but not great. Fitted a new starter motor but he thinks it turns over slower than his old one.
Has had his injectors serviced but still hard to cold start. His compression is really good (tested)
Head gasket has been replaced. Fuel lines checked for flow. All that's left is to have the injector pump serviced

 

[vyv_cox]

Inability to rev is commonly caused by blocked fuel filters. That may also be the cause of your starting problem.

 

[DangerousPirate]

The 1GM10 doesn't have heaters and so will always be more difficult to start in winter. Mine starts instantly in the summer but needs a bit of a churn in cold weather.
Check the compression if you can. Is it hard to turn over the compression stroke with the handle?
Check for blockages in the exhaust elbow and hose.
Check for fuel blockages or air leaks in the fuel line.
Try spinning it up with the decompression lever up for a few seconds so the momentum carries it over the first compression strokes.
The alarm when under load could be overheating. Does the top of the block feel very hot?

I tried spinning it with the compressor lever up and then let it go. It doen't work. I tried this in neutral and at different speeds, nothing changed.

I remember having used the engine in weather even colder than this before and it was no issue then. That was maybe in October, maybe November. That was the last time I checked it.


Bleeding air is difficult due to the inaccessibility of the required nuts.Especially the one on the starboard side of the engine. Ugh. Wish I had a bigger engine bay now.

 

[DangerousPirate]

Inability to rev is commonly caused by blocked fuel filters. That may also be the cause of your starting problem.

Okay, that is something I will check next. You sound very confident about this.

 

[vyv_cox]

Okay, that is something I will check next. You sound very confident about this.

Yes, i have experienced it several times in boats, particularly after long layups followed by vigorous sailing, but also on road vehicles. Blocking of the primary filter leads to vacuum in downstream pipework and secondary filter that can draw in air, affecting starting.

 

[Pye_End]

Remember to close the raw water sea cock if having trouble starting, till it is going.

I think the cold start procedure for these engines if full throttle? Perhaps someone can confirm. As others have said, not an easy cold starter, but revs dropping off when running - fuel filters are a good place to start as Vyv says.

 

[DownWest]

Agree with Viv, most of your symptoms could be from fuel flow problems. Had very similar with a duff fuel pump on the same engine. Trouble starting, wouldn't rev.
On throttle setting, most simple diesels have the rack set 'rich' until they start, then the governor takes over at whatever the throttle is set at. There is not a direct connection between the throttle and fuel flow. Having said that, Yanmars do seem to need a throttle setting at above tick over.

 

[QBhoy]

First thoughts would be around the fuel system and fuel quality. That’s the optimistic option. The pessimistic thinker might ask if you winterised the engine ? If you didn’t…has there perhaps been some frost damage allowing water ingress or perhaps a loss of compression as a result of or caused by.

 

[jamie N]

I'd a similar problem. I found that the gasket between the rocker cover, which held the decompression lever had flattened a bit, so that the decompression lever was constantly slightly engaged. When I tried to start the engine with the rocker cover loose, it started 1st time, which led me to the solution.