1GM10 Starting Woe...

langstonelayabout

langstonelayabout

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Having some probs with my 1GM10 engine starting.

It starts about the sixth (extended) crank. Before the engine finally catches and starts I'm pumping loads of blue smoke out of the exhaust but once it runs, it runs properly and starts properly all weekend.

Anyone any thoughts? I'm taking it out for a look-see this winter and would appreciate your thoughts of the potential cause. When it runs it runs well, if a little warm. The fuel (road-legal white diesel) is about a year old.

Many thanks in advance
 
Sounds like the engine is not easily reaching sufficient pressure in the cylinders to fire. There can be several causes, compression is down or engine not turning fast enough. My guess is the latter, my old Thornycroft was like that till I replaced the leisure battery used for engine start with a proper starter battery, The extra initial kick from the extra CCA available made all the difference. A good long run at decent power can also help say 8 hours at cruising revs could help a lot too and only costs a little diesel
 
From a similar issue on a car---------Does it have preheat glow plugs?If they are not working the engine has to start on compression of cold fuel only.That takes a lot more wellie than with a glow plug.Ignore me if it doesnt have heaters.:ambivalence:
 
Biggles Wader said:
From a similar issue on a car---------Does it have preheat glow plugs?If they are not working the engine has to start on compression of cold fuel only.That takes a lot more wellie than with a glow plug.Ignore me if it doesnt have heaters.:ambivalence:
Click to expand...

Nae preheat on a 1GM10. Mine started fine today, on the Clyde, but took about ten seconds of cranking rather than the usual two ... I'm guess that's because it's a tad chilly here.
 
Are you giving it full throtle? My 2GM20 usually starts on the button unless it's really cold but it does need full throttle.
 
Try putting heat into the engine, at the moment I am waiting for the chance to change the glow plugs on my Perkins, I put hot air gun in the air intake, it starts instantly... Without heat it takes minutes of cranking.
 
Decompression

langstonelayabout said:
Having some probs with my 1GM10 engine starting.

It starts about the sixth (extended) crank. Before the engine finally catches and starts I'm pumping loads of blue smoke out of the exhaust but once it runs, it runs properly and starts properly all weekend.

Have you tried lifting the decompression lever?
Click to expand...
 
I had similar problems with my 1GM10, compression was good and battery was new. It turned out to be a tiny air leak, Changed all the fuel union copper washers and it fixed the problem. I have heard that sometimes the fuel filter housing can cause air to get into the system. If you replace the copper washers buy a box of them on-line, they are stupidly expensive from Yanmar (like everthing else!). Wehn I say tiny I mean tiny, you could hardly see a trace, just a mist of fuel near the union. It doesn't take much to cause a starting problem.

One thing we always do is to leave the engine just past compression, this gives the starter a ful cycle to compression to get the flywheel moving fast.
 
Just worked on a friends ysb12. I ended up:

Regrinding valves,
New head gasket,
New piston rings
New injector nozzle and pressure tested it,
Checked the timing.

And this was one that had sat for a year without being used on the basis the head gasket had gone as it looked like someone had 'preheated it with a blow lamp.
Starts easily now and runs as sweet as a single cylinder diesel can!

Worth getting to the bottom of though and strikes me they are quite solid little engines.

Good luck with it.
 
Good that you got it running well. However, the 1GM is a completely different engine from the YSB and has its own (different) foibles.
 
Does sound rather like a compression problem. To get some more information, try squirting an oil can into the air inlet, not the air cleaner, while the engine cranks over. This will coat the bore and piston rings, improving the sealing of them. If it starts immediately it suggests the rings are poor. If it doesn't then it's something else. Check tappet clearances in case one is closed, holding a valve open.
 
The gm10 is single cylinder so if one valve was stuck closed , it wouldn't start at all. Also, afaik they don't have glow plug so all solutions relating to them are incorrect. I've not had a gm10 but had a 2gm20, this needed fullish throttle to start when cold. Agree that compression and correct tappet clearance should be checked and will aid starting and running.
vyv_cox said:
Does sound rather like a compression problem. To get some more information, try squirting an oil can into the air inlet, not the air cleaner, while the engine cranks over. This will coat the bore and piston rings, improving the sealing of them. If it starts immediately it suggests the rings are poor. If it doesn't then it's something else. Check tappet clearances in case one is closed, holding a valve open.
Click to expand...
 
IIRC the book gives the cold starting method as open to full throttle, then reduce to half throttle, then crank. The reason is that opening to full throttle without the governor spinning allows the fuel rack to open further than the normal stop, where it stays until the governor kicks in. This gives the engine a rich mixture during cranking to aid starting. Best to check the book as my memory isn't all it could be, but as the engine doesn't have a heater this procedure is critical to a good start.

Rob.
 
ghostlymoron said:
The gm10 is single cylinder so if one valve was stuck closed , it wouldn't start at all. Also, afaik they don't have glow plug so all solutions relating to them are incorrect. I've not had a gm10 but had a 2gm20, this needed fullish throttle to start when cold. Agree that compression and correct tappet clearance should be checked and will aid starting and running.
Click to expand...

I dont wish to piss on your fireworks, but if one valve was stuck closed it would be due to another fault.

The valve gear would be broken-anywhere from the cam operating the offending valve up to the rocker arm.

I favour-as others have suggested- set the engine JUST past compression, full throttle and hit the starter.

I could hand start the 1GM10 in the Hunter 27 OOD I had a share in.

Giving a diesel full throttle puts a little more fuel in the cylinder-or cylinders-and has the effect of increasing the compression a tad.

Worth a punt....................
 
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