3 cylinder yanmar not running.

[mattnj]

Hi,

I have a generator I am trying to get running (bought it as a non runner) it is a yanmar 3TNE68 3 cylinder 17hp I think. If I let the plugs heat then crank it runs everytime for about 1second. If I try immediately to restart it stutters and never runs, sounds like it's trying on 1 cylinder and turns over assisting the starter motor.
If I leave for about 1min the plugs heat again and it does the same thing (runs ok for about 1sec)

I have replaced the fuel, bled it to death, replaced filters, no difference. If I remove the 3 connections to the injectors there appears to be a healthy squirt coming out of each connector although if I disconnect the return from injectors and crank nothing comes out of that which seems a bit odd?

And ideas anyone on what to look at next?

Other thing worth mentioning is that it appeared to over overfilled with oil by about 1" on the dipstick! Which I have now drained out.

Thanks.

 

[dingdongs]

fuel pump timing may need checking. May be on a on a tapered shaft and will require a workshop manual for procedure.
http://www.yanmarengines.co.uk/detail.php?product_id=46
the service manual pdf file in the download will show you how to check fuel pump timing

 

[mattnj]

fuel pump timing may need checking. May be on a on a tapered shaft and will require a workshop manual for procedure.
http://www.yanmarengines.co.uk/detail.php?product_id=46
the service manual pdf file in the download will show you how to check fuel pump timing

Thanks for that, looks like it's adjusted with shims so can't really see how it would have changed.

 

[Topcat47]

If it only runs with the glow plugs on, it sounds like low compression. Of course the only way to measure it is to remove the injectors. Try the hand crank, if you can turn it over through two revolutions, that's probably the problem. The head gasket can fail between two of the cylinders without allowing gases into the water jacket.

 

[mattnj]

If it only runs with the glow plugs on, it sounds like low compression. Of course the only way to measure it is to remove the injectors. Try the hand crank, if you can turn it over through two revolutions, that's probably the problem. The head gasket can fail between two of the cylinders without allowing gases into the water jacket.

I will see if I can get it compression tested.

 

[Marsupial]

Hi,

I have a generator I am trying to get running (bought it as a non runner) it is a yanmar 3TNE68 3 cylinder 17hp I think. If I let the plugs heat then crank it runs everytime for about 1second. If I try immediately to restart it stutters and never runs, sounds like it's trying on 1 cylinder and turns over assisting the starter motor.
If I leave for about 1min the plugs heat again and it does the same thing (runs ok for about 1sec)

I have replaced the fuel, bled it to death, replaced filters, no difference. If I remove the 3 connections to the injectors there appears to be a healthy squirt coming out of each connector although if I disconnect the return from injectors and crank nothing comes out of that which seems a bit odd?

And ideas anyone on what to look at next?

Other thing worth mentioning is that it appeared to over overfilled with oil by about 1" on the dipstick! Which I have now drained out.

Thanks.

remove the injectors and see if they spray - it sounds like they're stuck.

 

[rob2]

This would belong on another thread (confessions) if it were not boaty...

I was once trying to get a yanmar twin running, though we only had a borrowed manual reprint - and that had only the odd pages, no even numbers! Following the instrctions, I partly dismantled the injector pump. On reassembling everything, it would only run on one cylinder, although it fired on both during start up. I believe the mechanism for this was that although mistimed, enough fuel was injected into the cylinder for it to fire a couple of times initially.

A local diesel engineer kindly rebuilt the pump without laughing at me too much - even showed us the missing page where the preceding paragraph told that the following information was for information only and should not be attempted by anyone without the jigs and test equipment to successfully complete the job. Anyway, we had not disturbed the adjusting shims, so when reinstalled the pump the engine ran beautifully. The point is, that someone may have mucked up the pump and it would be well worth while having it and the injectors serviced once you have done a compression check. Assuming you have good compression, then it would give you a clean running reliable engine for years to come.

Good luck with it, once fettled you will be so proud of it!

Rob.

 

[gordmac]

Have you tried a blowlamp heating the intake air? Has it been lying unused for a long time? If so maybe the rings are a bit stuck.

 

[mattnj]

Have you tried a blowlamp heating the intake air? Has it been lying unused for a long time? If so maybe the rings are a bit stuck.

er no, not tried that, what just blast a naked flame into the intake whilst cranking? sounds fun/dangerous?

 

[mattnj]

This would belong on another thread (confessions) if it were not boaty...

I was once trying to get a yanmar twin running, though we only had a borrowed manual reprint - and that had only the odd pages, no even numbers! Following the instrctions, I partly dismantled the injector pump. On reassembling everything, it would only run on one cylinder, although it fired on both during start up. I believe the mechanism for this was that although mistimed, enough fuel was injected into the cylinder for it to fire a couple of times initially.

A local diesel engineer kindly rebuilt the pump without laughing at me too much - even showed us the missing page where the preceding paragraph told that the following information was for information only and should not be attempted by anyone without the jigs and test equipment to successfully complete the job. Anyway, we had not disturbed the adjusting shims, so when reinstalled the pump the engine ran beautifully. The point is, that someone may have mucked up the pump and it would be well worth while having it and the injectors serviced once you have done a compression check. Assuming you have good compression, then it would give you a clean running reliable engine for years to come.

Good luck with it, once fettled you will be so proud of it!

Rob.

Know anyone localish (West Sussex/Worthing/Horsham area)?

 

[gordmac]

er no, not tried that, what just blast a naked flame into the intake whilst cranking? sounds fun/dangerous?

More across than into really, what you need to do is warm the air going in. Started a few reluctant diesels like that. Not dangerous with a diesel, it is dangerous with a petrol though!

 

[mattnj]

It was a completely blocked exhaust. Hard to spot as internal but that fixed it immediatly!