yanmar 1gm 10, injector pump removal

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help please, my engine starts and runs at mid revs sweetly for 20 seconds then slows to stall in the next 10. it will then restart easily and do the same again. all pipes,filters and lift pump have been completely cleaned and tried with fresh diesel. i am now looking at the injector pump. how does it come out? any advice is welcome, also best workshop manual to buy and where from thanks
 
From previous posts on this, I would suggest checking the exhaust before anything else:

Check hose isn't blocked & *remove* the exhaust elbow to check for carbon build up. There isn't an exhaust sea-cock, is there....?

See Dogwatch's post further down for some more general information.

Andy
 
Highly unlikely it is the pump. Symptoms suggest air getting in, so bleed all the points. Alternative is back pressure in the exhaust, although this usually results in poor starting as well.

For a manual suggest you buy the official Yanmar manual from a Yanmar dealer if you intend taking things apart. Very detailed, not so good on diagnosis but invaluable if doing any serious dismantling and re-assembly.

You don't say when or how the symptoms came about. Has it run OK before?
 
thanks for both replies, i wasnt looking forward to removing the injector pump and the exhaust blokage sounds a possibility. It was running fine and then slowly lost revs and died. Since then it will restart without any problem but within 30 seconds it has died again. it doesnt respond to the throttle at all. The throttle and stop levers are working as they should.
For the 30 seconds it runs it sounds fine.
I will try the exhaust elbow on my next visit and repot back. thanks again
 
Could it be a problem with the governor. A common problem with starting these engines is that the governor spring is weak and the governor rack returns too quickly. Could be you have the opposite problem. Perhaps if yours is stuck in position it allows it to start but does not return when it should thus causing it to conk out.
remove oil cap, reach in with left index finger and feel for a lever just off to the right hand side of the hole as you look at it.Check this moves freely.
Another possible problem is the throttle lever is prone to getting stuck. remove the split pin and detach the throttle cable. Then make sure that the lever moves freely. In the past i have had to free mine up with wd40.
Just some ideas. Dont quote me unless they work!
 
[ QUOTE ]
help please, my engine starts and runs at mid revs sweetly for 20 seconds then slows to stall in the next 10. it will then restart easily and do the same again. all pipes,filters and lift pump have been completely cleaned and tried with fresh diesel. i am now looking at the injector pump. how does it come out? any advice is welcome, also best workshop manual to buy and where from thanks

[/ QUOTE ]

How did you "clean" the filters ? This sounds like a problem we had after a long lay off where a thin film had formed over the surface of the filter in the water separation filter. The engione would start but was almost totally non-responsive and lack any power, then would die.
Fitted a new element and off it went sweet as a sweet thing...

Another possibility could be your fuel tank vent blocked ?
 
I agree with Tranona - air in the pipes. In fact, I would bet that it is in the high pressure pipe between the pump and the injector. Start the engine and crack the union open at the injector, and tighten again immediately. Do this 2 or 3 times and it should clear. If you do it quickly enough you can re-tighten it before the engine stops, and it will pick up again and carry on running. Usually, because the engine is shaking about the spanner slips off and the engine stops, but it shouldn't make any difference to the effectiveness of the bleeding operation.
Only move on to the exhaust bend inspection if this fails to work.
 
to add to the others comments when the elbow is off stick your finger in the exhaust port and make sure it hasnt carboned up, the last one i saw had reduced to the size of a pencil !
 
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