Diesel M-25 won't start

[sailaway78]

jaydog

are you sure the starter is spinning this puppy over fast enough. All a diesel basically needs to fire up is fuel and a good spin. If the starter is turning it over fast enough, and the system has no air in it, it should start. There a a lot of things that could be wrong, but since all you did was change the filters, has to be something to do with that.

 

[sailaway78]

jaydog

are you sure the starter is spinning this puppy over fast enough. All a diesel basically needs to fire up is fuel and a good spin. If the starter is turning it over fast enough, and the system has no air in it, it should start. There a a lot of things that could be wrong, but since all you did was change the filters, has to be something to do with that.

 

[Bill Roosa]

High pressure side bleeding???

Ok I understand all the low pressure side stuff. Nothing new here. But once the injector pump is primed is it not going to FORCE more fuel into the high pressure side no matter how much air is trapped in it??Since the injector pump is primed it repeatedly puts a small amount of fuel into the high pressure line to the injector. The air inside absorbs the high pressure pulse at first but the injector pump is still forcing more fuel into the line. Eventually the air will get compressed high enough by the fuel to open the injector and let the air out.So I guess what I'm saying is the high pressure side (after the injector pump) is self priming.What am I missing?

 

[Bill Roosa]

High pressure side bleeding???

Ok I understand all the low pressure side stuff. Nothing new here. But once the injector pump is primed is it not going to FORCE more fuel into the high pressure side no matter how much air is trapped in it??Since the injector pump is primed it repeatedly puts a small amount of fuel into the high pressure line to the injector. The air inside absorbs the high pressure pulse at first but the injector pump is still forcing more fuel into the line. Eventually the air will get compressed high enough by the fuel to open the injector and let the air out.So I guess what I'm saying is the high pressure side (after the injector pump) is self priming.What am I missing?

 

[Stu Jackson]

jaydog, I assume you're using the

glow plugs?

 

[Stu Jackson]

jaydog, I assume you're using the

glow plugs?

 

[Don S/V ILLusion]

high pressure side air

BillThat's what I apparently did a poor job of describing previously - most injectors are self bleeding and should not require attention unless it has been removed. However, as with any generality, there is a problem; for example for Yanmar GM series, the manufacturer, who most would consider authoritative, recommends [to paraphrase]:"The engine should now start, if not you will have to bleed the high pressure side as follows: Crack the pipe nut at each injector, open the decompression levers and rotate the engine with the starter motor.When the air appears to have been purged (the fuel looks clear, not whitish), tighten the nuts firmly, close the decompression levers and start the engine. Check for leaks and clean up any spilt fuel."Universal service bulletins recommend a similar procedure.I have no doubt folks have done it differently with success - I'm only reiterating mfg recommended approach with some fundamental knowledge of how fuel systems pump.

 

[Don S/V ILLusion]

high pressure side air

BillThat's what I apparently did a poor job of describing previously - most injectors are self bleeding and should not require attention unless it has been removed. However, as with any generality, there is a problem; for example for Yanmar GM series, the manufacturer, who most would consider authoritative, recommends [to paraphrase]:"The engine should now start, if not you will have to bleed the high pressure side as follows: Crack the pipe nut at each injector, open the decompression levers and rotate the engine with the starter motor.When the air appears to have been purged (the fuel looks clear, not whitish), tighten the nuts firmly, close the decompression levers and start the engine. Check for leaks and clean up any spilt fuel."Universal service bulletins recommend a similar procedure.I have no doubt folks have done it differently with success - I'm only reiterating mfg recommended approach with some fundamental knowledge of how fuel systems pump.